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# /sci/ - Science & Math

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Formerly >>11120908

>do not introduce yourself or give irrelevant personal information
>explain what it is you want to do or know
>explain the general why behind it
>copy and paste "Thanks in advance." to the end of the post
>attach some image to bring attention to the post (actually works, believe it or not)

 >> Anonymous Thu Nov 14 13:22:53 2019 No.11146383 Today is a great dayIt's a day of learning mathIn this happy place
 >> Anonymous Thu Nov 14 13:52:19 2019 No.11146463 /sci/bros, rec me a good book for thermo I.
 >> Anonymous Thu Nov 14 13:55:19 2019 No.11146481 File: 1.41 MB, 1700x997, __hakurei_reimu_kirisame_marisa_remilia_scarlet_izayoi_sakuya_kochiya_sanae_and_11_more_touhou_drawn_by_maachi_fsam4547__6f6aaa00d64f991ffdb4bf545891aa60.jpg [View same] [iqdb] [saucenao] [google] [report] Unanswered questions from the previous thread:Math questions, exact subject in brackets (most of the time):>>11121253 [Stochastic processes.]>>11124498 followed by >>11135354 [Statistics.]>>11133059 >>11135296 [Graphs.]>>11135732 [Calculus.]>>11135898 [High school algebra, ennumeration problem.]>>11136817>>11144287>>11145316 [Combinatorics.]>>11145332 [Bolzano-Weierstrass theory.]>>11146319 [Linear algebra.]>>11145317 [Asymptotics or limits.] [Also answered, but I'm pretty sure it was answered incorrectly.]Physics questions:>>11121120>>11121790>>11128162 >>11135738 >>11142711 [At least I think it's physics.]Engineering questions:>>11120997Chemistry questions:>>11127484>>11136018>>11137410Alchemy questions:>>11145472Biology questions:>>11123397>>11126065>>11127002>>11127139>>11127399>>11139152>>11143246>>11145513/g/ questions:>>11128371>>11142078 followed by >>11142098 [Technically answered, but anon has specifically replied to the answer with a thanks for bumping, so I'll make an exception and put it here.]Stupid questions:>>11126032 >>11127993>>11128442>>11133845>>11139769>>11146195
 >> Anonymous Thu Nov 14 14:03:15 2019 No.11146504 >>11146481I recall that I didn't put a subject in the curve shortening flow one since the subject is "curve shortening flow", but I have absolutely no idea why I didn't add "module theory" to the other one.
 >> Anonymous Thu Nov 14 14:22:22 2019 No.11146536 Can sound waves transform into or run along magnetic waves?
 >> Anonymous Thu Nov 14 14:30:09 2019 No.11146554 File: 97 KB, 660x600, ff5d3611699a26abf51d0f19cea45890.png [View same] [iqdb] [saucenao] [google] [report] >>11135738No. Even assuming perfectly reversible processes, the maximum efficiency of a cycle is η=1-TL/TH (which is strictly less than 1) where TH is the thermodynamic temperature of your hot reservoir, and TL the temp of your cold resv. See Carnot's theorem.If you aren't talking about a thermodyanmic cycle, then yes, a particle can move through a potential field without losing energy. This is the definition of a conservative field.>>11120997check valves>>11145472acquire philosopher's stone
 >> Anonymous Thu Nov 14 14:31:29 2019 No.11146557 >>11146536Yes. That's how a microphone works.
 >> Anonymous Thu Nov 14 14:48:32 2019 No.11146587 My teacher calls Mn2O7 manganese(VII) oxide, but she also calls P2O5 diphosphorus pentoxide.Is it correct to write manganese heptoxide and phosphorus(V) oxide as well?
 >> Anonymous Thu Nov 14 15:17:56 2019 No.11146677 >>11146587Not a chemist, but I don't think that's acceptable simply because mangnese is a transition metal and phosphorus is not.
 >> Anonymous Thu Nov 14 15:21:11 2019 No.11146687 >>11146587Metal means you simply list oxidation state, non-metal you list structure. Check with the IUPAC nomenclature for exact definitions.
 >> Anonymous Thu Nov 14 16:27:02 2019 No.11146904 Asked this in a previous thread, but it didn't get answered because it was on the verge of dying.Is there any way to turn lead into a more useful element in an energy-efficient manner?I'm not a chemist of any sort, but I do know there's at least a decent amount of lead on Earth that we get as a byproduct of mining operations, and that there aren't a lot of good uses for it given how toxic it is to humans. It does have a high atomic weight though, so maybe if there were a way to either fission it or turn it into something fissionable, we could end up with a bunch of not-lead that we could use for something else.
 >> Anonymous Thu Nov 14 17:10:03 2019 No.11147039 How do we know the universe is infinite?
 >> Anonymous Thu Nov 14 17:11:06 2019 No.11147040 What particles are we 100% sure exist?
 >> Anonymous Thu Nov 14 17:24:29 2019 No.11147074 What was before the big bang?
 >> Anonymous Thu Nov 14 17:40:36 2019 No.11147099 >>11146904You don't need to repost, see >>11146481>>11147039We don't and it probably isn't.>>11147040None, go read Hume or Descartes.If you mean "what's the general experimentally verified consensus", go look up the standard model page in wikipedia.>>11147074Last I checked, general consensus is that there was no before the Big Bang.
 >> Anonymous Thu Nov 14 17:43:29 2019 No.11147107 do chads carry genes for butch mannish women?do skinny incels carry genes for cute petite girls?
 >> Anonymous Thu Nov 14 17:44:26 2019 No.11147110 What's going to happen when we collide with Andromeda?
 >> Anonymous Thu Nov 14 17:45:29 2019 No.11147113 >>11147099>go look up the standard model page in wikipedia.Doesn't say
 >> Anonymous Thu Nov 14 17:52:44 2019 No.11147127 why do matter and antimatter go boom when they touch each other?
 >> Anonymous Thu Nov 14 17:55:12 2019 No.11147137 >>11147110A new, bigger galaxy will form over the course of millenniaProbably nothing will happen to the solar system because galaxies are mostly empty space so the chance of anything crashing into us is essentially zeroIf there are any humans left when that happens they won't even notice the merge is happening, except for the few scientists actively studying it
 >> Anonymous Thu Nov 14 17:58:09 2019 No.11147141 >>11147137>low chance of colliding with anything>low chance of any extraterrestrial life visiting us>low chance of anythingFuck the space it's so big for no reason and we gain nothing for studying it
 >> Anonymous Thu Nov 14 18:01:45 2019 No.11147154 >>11147141Space is unimaginably big and the speed limit is so relatively minuscule, the harsh truth is that even if there IS anything or anyone interesting out there chances are we'll never ever find it or get to do anything with it. But I wouldn't say there's nothing to gain by studying it, knowledge for knowledge's sake is not a bad thing
 >> Anonymous Thu Nov 14 18:04:28 2019 No.11147160 Would humans have come to be if the asteroid didn't kill the dinosaurs?
 >> Anonymous Thu Nov 14 18:06:13 2019 No.11147165 File: 101 KB, 609x827, d6zY3xu.jpg [View same] [iqdb] [saucenao] [google] [report]
 >> Anonymous Thu Nov 14 18:06:25 2019 No.11147167 >>11147099>there was no before the Big BangWouldn't that suggest the existence of a God then? Something has to be the eternal, and I would assume that would be the universe itself, but...
 >> Anonymous Thu Nov 14 18:07:05 2019 No.11147168 >>11147160Maybe, maybe not. How the fuck could anyone answer that when we're talking timescales of hundreds of millions of years
 >> Anonymous Thu Nov 14 18:08:07 2019 No.11147170 >>11147167>Something has to be the eternalwhy?
 >> Anonymous Thu Nov 14 18:08:48 2019 No.11147173 The derivative of |2x-2| would be $\frac{4x-4}{|2x-2|}$ right? Or do I not understand how to derive absolute functions?
 >> Anonymous Thu Nov 14 18:10:14 2019 No.11147178 >>11147168Through thought exercises you retarded empiricist
 >> Anonymous Thu Nov 14 18:10:48 2019 No.11147181 >>11147127also is there an antimatter equivalent of light? if we had a big enough chunk of antimatter that we could somehow contain in a vacuum so it wouldn't explode, would "normal" light do anything to it or does annihilation only happen with particles that have mass?
 >> Anonymous Thu Nov 14 18:13:16 2019 No.11147186 >>11147181the anti-particle of a photon is a photon
 >> Anonymous Thu Nov 14 18:23:03 2019 No.11147206 If you have an interval and a function is not differentiable at a certain point in that interval, is it true to say "the function is not differentiable on the interval" or should you say "the function is not differentiable at a point in the interval" or something else?It's for a question about the mean value theorem.
 >> Anonymous Thu Nov 14 18:23:12 2019 No.11147207 >>11147178Not science and not math
 >> Anonymous Thu Nov 14 18:23:33 2019 No.11147208 >>11147173Strictly speaking it doesn't have a derivative, since the function isn't derivable at 2x-2=0 (so x=1) which is part of the maximal domain of the absolute value. That said, if you define the function just on the intervals (-inf,1) and then (1,inf), you could define the derivative without issues. But for x<1, 2x-2 is negative, so the absolute value just becomes 2-2x, and for x>1, the absolute value remains the same so you have 2x-2. And you can probably find the derivative of either of those very easily.From you solution, you have if x<1 then the derivative would be (4x-4)/-(2x-2)=-2, and (4x-4)/(2x-2)=2, if x>0. Which matches up almost perfectly with the results above, however you still need to get rid of the case x=1, since then the fraction becomes undefined and in general the derivative isn't defined.
 >> Anonymous Thu Nov 14 18:27:25 2019 No.11147219 >>11147206Differentiability is a local property, saying a function is differentiable is just a short way of saying that it is differentiable at each point in it's domain. If a function is not differentiable at a point (even just a single one), then the proper thing to say is that the function as a whole isn't differentiable, or it is not differentiable in its domain. Of course you can change the domain by adding certain restrictions, but at that point you are technically working with a different function.
 >> Anonymous Thu Nov 14 18:28:29 2019 No.11147222 >>11147207Science can be used to simulate a model to approximate a result using assumptions and confidence intervals. Don't be upset you're a brainlet and can't approach questions that are not solved in your textbook.
 >> Anonymous Thu Nov 14 18:29:58 2019 No.11147226 >>11147222there is no model anywhere in all of biology that comes close to modeling evolution over thousands and thousands of generations, retard.
 >> Anonymous Thu Nov 14 18:30:29 2019 No.11147229 >>11147219Thanks very much.
 >> Anonymous Thu Nov 14 18:38:27 2019 No.11147259 File: 48 KB, 800x615, dry spongey.jpg [View same] [iqdb] [saucenao] [google] [report] How the FUCK do I determine a sequence's convergence? As in how do I execute it? I know the definitions, |xn - limit| < ε for n>=N, etc., but I just can't ever really move forward from that whenever I have to do an actual exercise. How do I approach these exercises, what's the actual process to doing them? Please provide examples. 4th time I'm in some sort of basic Maths course in Uni and every time I get hung up on this shit and there goes the whole semester ;_;
 >> Anonymous Thu Nov 14 18:40:14 2019 No.11147268 is it a rule that if you have a=b/c you have c=b/a
 >> Anonymous Thu Nov 14 18:48:02 2019 No.11147307 >>11147268a=b/cac=bc=b/aChecks out for the most part, except for cases where division by 0. If b=0, the whole thing blows up because...a=0/c, therefore a=0c=0/0 <- this isn't acceptable.
 >> Anonymous Thu Nov 14 18:48:42 2019 No.11147312 >>11147268yes, this is always true so long as a=/=0
 >> Anonymous Thu Nov 14 19:40:21 2019 No.11147487 Doing the improper integral of xSinx/(x^2+2x+2) from -infinity to infinity through the complex plane, using the Cauchy theorem. However, I end up with a complex number result from the integral of the full semicircle in the complex plane, when the result should be entirely real, given that the curve part of the integral should go to 0. Am I fucking up my calculations or am I missing something?Thanks for the help
 >> Anonymous Thu Nov 14 19:40:25 2019 No.11147488 File: 2.69 MB, 494x360, final_5dcdf3923d0e070014e001ef_941525.gif [View same] [iqdb] [saucenao] [google] [report] What type of math describes the stuff you'd expect to see in a "Satisfying mechanisms compilation"?
 >> Anonymous Thu Nov 14 19:55:18 2019 No.11147524 >>11147488engineering mathematics ;3
 >> Anonymous Thu Nov 14 20:40:29 2019 No.11147626 What do i do if i wanna learn college level stuff but dont wanna interact with others or spend money or take tests but im also not self motivated enough to study onmyown
 >> Anonymous Thu Nov 14 20:46:32 2019 No.11147643 >>11147626Depends where you live. If you're in a first world country, there's probably some university around that doesn't have entry checks, which means you could just go and sneak into a class.
 >> Anonymous Thu Nov 14 20:48:24 2019 No.11147648 >>11147643im too paranoid to do that consistently, and the one time i did do that it was just a lecturer with a thick hindi accent proving theorems. if i wanna read proofs i can easily do that alone, thats hardly a lesson lol
 >> Anonymous Thu Nov 14 21:01:25 2019 No.11147680 File: 951 KB, 1800x1800, __flandre_scarlet_and_remilia_scarlet_touhou_drawn_by_sakurea__07b409c51a76f6044187f407f7a88f95.png [View same] [iqdb] [saucenao] [google] [report] >>11147488In all honesty, the two single smoothest and most immediately beautiful things in maths are complex analysis and symplectic geometry (in particular applied to mechanics).Some other subjects are more attractive than either, such as contact geometry or sheaf theory, but those take time.>>11147626>I don't wanna interact with others>I don't wanna study on my ownYou'll need to either settle for studying with other people or without other people, there is no third option.
 >> Anonymous Thu Nov 14 21:03:40 2019 No.11147682 >>11147074Time didn't exist until the big bang so how can there be a before
 >> Anonymous Thu Nov 14 21:28:20 2019 No.11147731 Is there a term for a type of hypothetical particle that exists at multiple points in time simultaneously? That is, if you emit there particles through a room, they will cast a shadow on the wall with the outlines of future things that would pass through that room, because they get blocked by future objects as well as present objects.Pretty sure this doesn't describe tachyons and is instead something else. Also, does anything in physics hard disallow this? Because I feel this is a pretty tame way to "time travel".
 >> Anonymous Thu Nov 14 21:29:43 2019 No.11147735 >>11147680well, id like to study with guidance and Human, i just meant i dont want to be around tons of shitty normies in a Uni setting
 >> Anonymous Thu Nov 14 21:30:57 2019 No.11147741 >>11147735Sounds like you have a problem with your ego. Stop that.
 >> Anonymous Thu Nov 14 21:32:52 2019 No.11147749 >>11147735How much money do you have?
 >> Anonymous Thu Nov 14 21:37:42 2019 No.11147764 >>11147741a little bit yeah, but thats not the relevant cause. i just have social issues (ones not mainly stemming from ego)>>11147749not that much
 >> Anonymous Thu Nov 14 21:39:47 2019 No.11147771 >>11147764>i just have social issues (ones not mainly stemming from ego)Well, those can be fixed. And the best way is to interact socially. There's nothing wrong with normal people, anon. Good luck~
 >> Anonymous Thu Nov 14 21:41:00 2019 No.11147774 >>11147771i dont wanna interact socially and yes normally people are cruel and i dont have money or mental stability for uni anywayso how do i learn me some differential geometry?
 >> Anonymous Thu Nov 14 21:51:40 2019 No.11147814 >>11147774>yes normally people are cruelMost people are not cruel. I promise.>so how do i learn me some differential geometry?Years and years of study. You have to know the easy stuff before you know the hard stuff.
 >> Anonymous Thu Nov 14 22:27:54 2019 No.11147916 >>11147488Is that device more complicated than it needs to be?
 >> Anonymous Thu Nov 14 22:28:32 2019 No.11147919 >>11147731>multiple points in time>simultaneouslysimultaneity is a concept referring to occurence of events at the same time
 >> Anonymous Thu Nov 14 22:28:53 2019 No.11147922 >>11147916doesnt look like it
 >> Anonymous Thu Nov 14 22:48:22 2019 No.11147983 >>11147919But you understand what I mean. A particle that has a chance to collide with barriers that will block its path in the future, jumping forward in time as it does so.
 >> Anonymous Thu Nov 14 22:52:24 2019 No.11147995 >>11147983if it collides with those barriers now then those barriers block it now rather than in the future
 >> Anonymous Thu Nov 14 23:58:13 2019 No.11148151 >>11147170Nothing -> Something doesn't make logical sense.
 >> Anonymous Fri Nov 15 00:00:34 2019 No.11148159 >>11148151based on logical first principles, explain why
 >> Anonymous Fri Nov 15 00:15:24 2019 No.11148180 File: 2.00 MB, 310x368, 1573343844897.gif [View same] [iqdb] [saucenao] [google] [report] What's the tern that describes the condition where one point continuously approaches another stationary point for infinity? Such as in the case of repeatedly halving a number forever with respect to zero.
 >> Anonymous Fri Nov 15 00:34:58 2019 No.11148202 >>11148180A limit.
 >> Anonymous Fri Nov 15 02:03:00 2019 No.11148384 How do the brain worbk
 >> Anonymous Fri Nov 15 03:41:10 2019 No.11148547 >>11148180Convergence?
 >> Anonymous Fri Nov 15 04:07:01 2019 No.11148587 what exactly are the specs of a 75ohm attenuation and where can i find out more info on the subject, possibly equations to help me attenuate video and sync signals
 >> Anonymous Fri Nov 15 06:05:36 2019 No.11148734 Can someone tell me if I understood addressing in x86 correctly?Let's say we have address of something in ebx, ebx equals that address and [ebx] equals to whatever is stored in that addressebx[esi] is the same thing as [ebx + esi]Now the thing that confuses me:if there's mem1 declared in .data, both mem1 and [mem1]afaik mem1 and ebx are the same thing as offset mem1 and offset ebx, because assembler just assumes that it's what we meant, because having real address doesn't have sense
 >> Anonymous Fri Nov 15 06:45:16 2019 No.11148781 >>11148151bruh, think one step back. If you cant have something from nothing what came before God?
 >> Anonymous Fri Nov 15 06:47:30 2019 No.11148784 >>11148781That's the point, God is literally defined as the something that stops the infinite regress. This doesn't imply that God has any particular properties like being the Biblical God or whatever, it just literally identifies the concept of the necessary, non-contingent being with that word.
 >> Anonymous Fri Nov 15 06:52:31 2019 No.11148786 >>11148784I mean you still have to prove the necessity of a 'God' and Occram's razor would suggest you don't need it.
 >> Anonymous Fri Nov 15 06:59:21 2019 No.11148793 >>11148786Is logical necessity not sufficient? Reminder, you have an emotional reaction to the word "God". Pick another term if you like, but if you accept that all contingent things have causes, denying that there is some non-contingent thing at the beginning actually makes things much hairier and harder to justify. You don't automatically become a Christian fundamentalist if you accept this argument.
 >> Anonymous Fri Nov 15 07:04:03 2019 No.11148798 >>11148793I don't believe a 'prime cause' or whatever the terminology is is a logical necessity. Especially when it could probably never be proven and therefore void/ indistinguishable from no cause. Also its 2am and I'v had too many beers.
 >> Anonymous Fri Nov 15 08:32:48 2019 No.11148906 File: 168 KB, 660x850, 1423779740722.jpg [View same] [iqdb] [saucenao] [google] [report] While making an erotic text game I came across this problem:I have some variable $F$ which changes as a function of $w$.For any given starting value $w_0$ and a change in $w$ of $\Delta w$, the relationship is thus:[eqn]F(w_0+\Delta w)=\dfrac{w_0f(w_0)+D\Delta w}{w_0+\Delta w}[/eqn]Where:$D$ is a parameter $0\leq D\leq 1$ that changes according the player's actions in the game.$f(w_0)$ is some other function. Right now it is defined as $f(w_0)=\dfrac{w_0}{71.6h^2}$ ($h$ is some constant), but it could change in the future to $f(w_0)=\dfrac{w_0}{64.1h^2}-0.176$.So to put it another way:[eqn]F(w_0+\Delta w)=\dfrac{\dfrac{w_0^2}{71.6h^2}+D\Delta w}{w_0+\Delta w}[/eqn]Is there a way to make this into a nice little $F(w)$ expression?I COULD just program the entire thing as-is directly into the game code, but I need to determine the exact values of $D$ to plug in there. I don't want to manually test out values between $0$ and $1$.Is such a function even possible..?Someone please help me out, I've never been good at calculus
 >> Anonymous Fri Nov 15 08:45:09 2019 No.11148919 File: 251 KB, 1060x1500, 1468593283717.jpg [View same] [iqdb] [saucenao] [google] [report] >>11148906oh and in case anyone's wondering,$F$ is the bodyfat percentage of the player.$w$ is the player's weight$h$ is the player's heightThis function is basically to calculate the bodyfat % as the player gains/loses weight.The two $f(w)$ functions are linear regressions of data I found on fat% vs. BMI (body mass index) for men and for women.$D$ is some parameter that should change according to how much exercise the player has accomplished.If anyone has a better idea of how to go about this, I'd be happy to hear it.
 >> Anonymous Fri Nov 15 09:44:04 2019 No.11149011 >>11148906>>11148919>simplify the functionCan't see any way of doing it and doubt there is one.>linear regressions on fat% vs. BMIThat makes absolutely no sense. You do know that BMI is only a function of height and weight, right? It can't differentiate muscle and fat, so it false positives when you give it athletic people. Did you test your linear regression for validity?My recommendation is simple. Set w=e+f+m, where w is weight, e is "essential weight" given by organs, bones and the like, f is fat and m is muscle.E is constant, the variation of f is calories consumed minus calories burned times a constant, and variation of m is a function of exercise (a logarithm might work, but it all depends on how exercise is measured in game).
 >> Anonymous Fri Nov 15 09:51:09 2019 No.11149023 should i apply for a masters or straight to the phd if im in the US?
 >> Anonymous Fri Nov 15 10:58:38 2019 No.11149134 File: 60 KB, 1271x579, Development_and_validation_of_two_equations_based_.jpg [View same] [iqdb] [saucenao] [google] [report] >>11149011>You do know that BMI is only a function of height and weight, right? It can't differentiate muscle and fat, so it false positives when you give it athletic people. Did you test your linear regression for validity?BMI is defined as $w/h^2$. You're right, it can't differentiate muscle and fat, but there is a statistical correlation between BMI and bodyfat, which is where I got that linear regression from. >Set w=e+f+m, where w is weight, e is "essential weight" given by organs, bones and the like, f is fat and m is muscleThe problem is that I'm trying to keep it very grounded and realistic. While I could just arbitrarily set the player to gain +X muscle mass when they exercise and +Y fat when they overeat, that's not how real bodies work. You don't just magically gain muscle when you work out, and you don't magically gain fat with no muscle when you get fat. These things go together, and I'm trying to figure out a reasonably accurate relation between them.So if the player wants to gain muscle, they will need to both exercise AND have enough food. In a roundabout way, that's what I've done. I've combined what you call "essential weight" with muscle mass under Lean Body Mass (LBM). This way I only have two real variable: Total body weight, and bodyfat %. LBM is then $LBM=(1-f)w$Looking back at >>11148906, I realize it probably wouldn't work out. What I should do is look at some sort of a function that looks like[eqn]F(w+\Delta w)=a\dfrac{w+D\Delta w}{w+b \Delta w}+c[/eqn]and find $a, b, c, D$ values that make it similar enough to the $f(w)$ in an appropriate range of value (basically, use the linear regression as a benchmark for my new function).I still have no idea how to do it, or how fucking simplify that motherfucker. It looks like a college-level Calculus 1 problem but I'm a fucking dropout so wtf
 >> Anonymous Fri Nov 15 11:11:25 2019 No.11149153 >>11149134That's a fractional linear transformation, it doesn't admit simplification.>it doesn't work like thatIt doesn't, but it's still better than assuming constant muscle proportional to height (which is quite literally what the regression does).
 >> Anonymous Fri Nov 15 11:13:44 2019 No.11149157 Can someone explain in Layman's term what's an adjoint representation and one of the simplest real world example?
 >> Anonymous Fri Nov 15 11:16:33 2019 No.11149167 why do these stupid chemist niggas say 2,2 dimethyl propene instead of 2 dimethyl propene
 >> Anonymous Fri Nov 15 11:18:59 2019 No.11149169 >>11149167jk that doesn't exist hehe
 >> Anonymous Fri Nov 15 12:28:31 2019 No.11149309 >>11146481wow, that's very nice of you to type that up, fren. are you a "based janny"?
 >> Anonymous Fri Nov 15 12:31:52 2019 No.11149315   what's the healthiest way to ingest nicotine?
 >> Anonymous Fri Nov 15 12:33:44 2019 No.11149318 >>11149315gum
 >> Anonymous Fri Nov 15 12:41:05 2019 No.11149336 File: 1 KB, 188x85, dfgdf.png [View same] [iqdb] [saucenao] [google] [report] why the FUCK is this called 1,2-Cyclopropanediol instead of cyclopropanediol? Why does the 1,2 matter? what other forms could cyclopropanediol have?
 >> Anonymous Fri Nov 15 12:53:31 2019 No.11149360 File: 8 KB, 225x225, download.jpg [View same] [iqdb] [saucenao] [google] [report] >>11149336it's a rooster
 >> Anonymous Fri Nov 15 13:00:21 2019 No.11149377 >>11147259bls respond...
 >> Anonymous Fri Nov 15 13:03:58 2019 No.11149382 how can I ensure my vaping is minimally harmful? I don't have a vape yet but I'm running some prefunctory analysis before really considering budgetting for a vape
 >> Anonymous Fri Nov 15 13:08:50 2019 No.11149391 >>11149377>>11147259>tutorial.math.lamar.edu/Classes/CalcII/ConvergenceOfSeries.aspx>>11149382also, i wanted to ask if people notie a difference in the high between vaping and pipe smokingdoes this help?
 >> Anonymous Fri Nov 15 13:13:57 2019 No.11149396 >>11149382dont vape anything that claims to have added vitamins, esp vitamin C
 >> Anonymous Fri Nov 15 13:26:41 2019 No.11149429 File: 180 KB, 596x250, bio_box_expressionism.jpg [View same] [iqdb] [saucenao] [google] [report] If you guys had two years to read whatever you wanted to make yourself as employable as possible what would you read?
 >> Anonymous Fri Nov 15 13:29:24 2019 No.11149439 >>11149382>running analysis to consider budget before vapingWhat, lmao?
 >> Anonymous Fri Nov 15 13:29:27 2019 No.11149440 Why do nurses make me expose my entire hairy ass and then, inject me above the belt line?
 >> Anonymous Fri Nov 15 13:38:40 2019 No.11149456 File: 19 KB, 700x700, ring electron.png [View same] [iqdb] [saucenao] [google] [report] Why is symmetry used so much?
 >> Anonymous Fri Nov 15 14:12:20 2019 No.11149514 remi's 5 century unwashed feet!
 >> Anonymous Fri Nov 15 14:24:12 2019 No.11149535 >>11149439what do you not get? I'm trying to see how much vaping would cost (upfront cost and monthly upkeep), what the negative effects are, how to avoid them, and if the high is the same as cigarettes/pipe tobacco.
 >> Anonymous Fri Nov 15 14:25:23 2019 No.11149537 >>11149429"employable as possibe" is a broad goal. better to narrow it down to something more specific; that's the frist thing I'd do. and I'd probably aim for software developer work.
 >> Anonymous Fri Nov 15 14:39:18 2019 No.11149568 Wikipedia, in the "Quadratic Equation" article, says:$(x + \frac{b}{2a})^2 = \frac{b^2 - 4ac}{4a^2}$But clearly this isn't the case, right? The x is completely absent. Expanding the left hand side yields, obviously:$x^2 + \frac{xb}{a} + (\frac{b}{2a})^2$.wtf?
 >> Anonymous Fri Nov 15 14:45:08 2019 No.11149578 >>11149568Ok, I see:$a(x + \frac{b}{2a})^2 - \frac{4ac - b^2}{4a^2} = 0$$a(x + \frac{b}{2a})^2 = \frac{4ac - b^2}{4a^2}$But this is still very different from Wikipedia's entry.
 >> Anonymous Fri Nov 15 14:48:24 2019 No.11149588 File: 165 KB, 1191x1684, __remilia_scarlet_touhou_drawn_by_sasa_kichi__0e931e419910ad2ef269cb2218dbcea7.jpg [View same] [iqdb] [saucenao] [google] [report] >>11149456Simplifies calculations a lot.>>11149514No. Bad anon. Bad.
 >> Anonymous Fri Nov 15 14:49:08 2019 No.11149595 File: 273 KB, 1200x1659, __remilia_scarlet_touhou_drawn_by_fkey__d643419f06bf6a30f9a61440df58969c.jpg [View same] [iqdb] [saucenao] [google] [report] >>11149588I imagine the Remi's feet, after a long century of being a vampire, must be absolutely disgusting from marinating in sweat, grease and bacteria. When she removes her shoes at the end of the day, she probably gets flustered at just how smelly and toxic her bare feet are; her own body betraying all standards of decency by producing an unbelievably lewd and slimy, biohazardous zone of filth within her own footwear. Shoes designed to look pretty and appealing, now soiled and turned into unusable, smelly, ruined trash by her own festering feet. It's almost amazing how an odor so potent and foul can come from a girl so cute. What a contrast!The contrast would be captivating. On one side, you've got her beautiful, pale, shapely, happy feet. They're works of art, and can arouse anyone with their perfection. On the other hand, you've got endless of amounts of a stink so foul it can make plants wilt and birds fall from the sky just by spreading her toes! Imagine seeing the Remi dip her feet in the ocean and turning it into a bubbling, stinky green mess with her odor and killing all the fish, or having her grab your nose with them and make you take deep breaths!Remi's cute, pale, smelly, vampire feet!
 >> Anonymous Fri Nov 15 14:49:47 2019 No.11149597 >>11149535I think you are putting way too much thought into vaping. It makes no sense. Just fucking do it if you want and don't do it if you don't want. Smoking is a vice regardless.
 >> Anonymous Fri Nov 15 14:50:04 2019 No.11149598 >>11149568x is being solved for. x is the square root expression at the end
 >> Anonymous Fri Nov 15 14:52:52 2019 No.11149603 >>11149597i don't currently smoke or vape, and it's not like I'm going crazy about it - i.e if the little cartridges are going to cost $100 per month for casual use, that's ridiculous and i won't indulge the habit. similar logic applies if they make my lungs moldy or burnt, or if the high sucks compared to cigarettes/pipe tobacco (I don't want to spend$200 on equipment that doesn't even work for me). to me, all of this seems reasonable
 >> Anonymous Fri Nov 15 14:54:03 2019 No.11149606 >>11149598is the notation being used wrong? wikpedia is not saying "x =" (which I would understand), they are saying "(x + b/2a)^2 =", and to me it currently seems incorrect, which i'm sure is my fault but i don't see how
 >> Anonymous Fri Nov 15 15:06:54 2019 No.11149636 >>11149606>it currently seems incorrectit isn't. there wikipedia article is fine.
 >> Anonymous Fri Nov 15 15:15:16 2019 No.11149652 >>11149568>It can easily be seen, by polynomial expansion, that the following equation is equivalent to the quadratic equation: $ax^2+bx+c=0$$x^2+\frac{b}{a}x+\frac{c}{a}=0$$(x^2+\frac{b}{a}x+(\frac{b}{2a})^2)-(\frac{b}{2a})^2+\frac{c}{a}=0$$(x+\frac{b}{2a})^{2}-\frac{b^2}{4a^2}+\frac{4ac}{4a^2}=0$$(x+\frac{b}{2a})^{2}=\frac{b^2-4ac}{4a^2}$
 >> Anonymous Fri Nov 15 15:21:30 2019 No.11149660 >>11149606It's an intermediate step in the solution.ax^2+bx+c = 0=> x^2+(b/a)x+c/a = 0 (divide by a)=> (x+b/2a)^2-(b/2a)^2+c/a = 0 (complete the square)=> (x+b/2a)^2 = (b/2a)^2-c/a (move terms other than the square to the RHS)=> (x+b/2a)^2 = b^2/4a^2-c/a (expand (b/2a)^2)=> (x+b/2a)^2 = b^2/4a^2-4ac/4a^2 (multiply c/a by 4a/4a so the RHS can be factored)=> (x+b/2a)^2 = (b^2-4ac)/4a^2 (factor RHS)=> x+b/2a = ±√(b^2-4ac)/2a (square root both sides)=> x = -b/2a±√(b^2-4ac)/2a (subtract b/2a)=> x = (-b±√(b^2-4ac))/2a (factor RHS)The key trick is noting that (x+b/2a)^2=x+(b/a)x+(b/2a)^2, which has two out of three terms in common with the equation in standard form (after dividing by a so the leading coefficient is 1). Thus the equation can be rewritten so that x only appears once. Then it's just a matter of basic algebra to get it to a x=... form.
 >> Anonymous Fri Nov 15 15:23:45 2019 No.11149662 >>11149660> noting that (x+b/2a)^2=x+(b/a)x+(b/2a)^2,(x+b/2a)^2=x^2+(b/a)x+(b/2a)^2(missing ^2 in the first term on the RHS).
 >> Anonymous Fri Nov 15 15:39:18 2019 No.11149681 File: 110 KB, 930x584, trans.png [View same] [iqdb] [saucenao] [google] [report] can I use DFT optimized structures as geometries for coupled-cluster calculations?
 >> Anonymous Fri Nov 15 16:48:28 2019 No.11149805 >>11149660>>11149636>>11149652Ok, I realized I didn't distribute the negative after brought the "terms other than the square" to the RHS. Thanks! I kept getting 4ac-b^2 for the RHS numerator and it was buggin me. I probably should've stepped away from my work for a couple minutes and then re-evaluated before posting, lol.
 >> Anonymous Fri Nov 15 17:51:04 2019 No.11149986 Is there a word for the sum of something when you divide 1 by it?
 >> Anonymous Fri Nov 15 19:10:55 2019 No.11150191 >>11149986multiplicative inverse
 >> Anonymous Fri Nov 15 19:14:15 2019 No.11150201 What's the difference between magnitude and amplitude?
 >> Anonymous Fri Nov 15 20:07:00 2019 No.11150348 >>11150201google it? amplitude is a slippery concept sometimes, often used to denote many similar things
 >> Anonymous Fri Nov 15 20:40:26 2019 No.11150442 why there no solution quintic
 >> Anonymous Fri Nov 15 21:03:47 2019 No.11150489 File: 10 KB, 500x342, Capture.png [View same] [iqdb] [saucenao] [google] [report] Is there a definitive guide to algebra simplification? How do you know what the best form will be when finishing a problem? My textbook will leave something like e^-1/x in the denominator, but other negative rational exponents it will simplify to the denominator. Wouldn't it be easiest to always have a 1 in the numerator?
 >> Anonymous Fri Nov 15 21:56:04 2019 No.11150619 >>11149588I was thinking of mass quantization, and what that S(2) means.Turning a field into a group?The kinetic theory of gasses, inelastic container vs. ideally elastic particles?My thought on symmetry:1. An object can only go as fast as c before it's two separate objects (1 object and EM)2. If so, I can view it like a film strip at frequency c3. No difference between symmetrical rotating and staying still
 >> Anonymous Fri Nov 15 22:32:03 2019 No.11150708 >>11146481>>11120997It's a picture of two check valves in series, also known as a double-check backflow preventer
 >> Anonymous Fri Nov 15 22:36:09 2019 No.11150718 >>11146481>>11126065Look up glycemic index
 >> Anonymous Fri Nov 15 22:40:56 2019 No.11150730 >>11149537And if you're aiming for software development work you really want to do things instead of just reading about them. Having something to show is extremely important, especially if you don't have any formal qualifications.
 >> Anonymous Fri Nov 15 22:40:56 2019 No.11150731 >>111493361,1-CyclopropanediolReally stupid question
 >> Anonymous Fri Nov 15 22:49:17 2019 No.11150748 >>11150201Magnitude is typically used when speaking of the raw quantity of something.Amplitude is typically used when speaking of the maximum reoccurring value that occurs in some kind of sinusoidal or otherwise cyclic system.They are related because the amplitude of something is equal to the magnitude at it's maximum value.
 >> Anonymous Fri Nov 15 23:31:08 2019 No.11150847 What happens if you boil clorox bleach? Does it release chlorine gas or anything harmful?
 >> Anonymous Sat Nov 16 02:53:17 2019 No.11151311 >>11150748Hm, so that means the magnitude is the current value of something (that could be oscillating), while the amplitude is the coefficient basically, or the maximum magnitude attainable?Thank you!
 >> Anonymous Sat Nov 16 03:05:33 2019 No.11151322 File: 4 KB, 353x79, Untitled.png [View same] [iqdb] [saucenao] [google] [report] How do I take the limit of this? It's supposed to be 0, but I tried using a radical conjugate and I got infinity. Aren't limits at infinity supposed to be simplified first so there is no ambiguity? If I divide all terms by x (x^2 in the radical) the limit comes to 0, but I don't think you are allowed to do it that way. All the problems from the limit section make you turn these into fractions by using a radical conjugate.
 >> Anonymous Sat Nov 16 03:07:31 2019 No.11151326 >>11151322I meant to say the limit comes to b/a if you divide everything by x, not 0.
 >> Anonymous Sat Nov 16 06:05:58 2019 No.11151562 >>11150442Galois theory.>>11151322>0Divide both by b/a, because linearity. Basic sign analysis will tell you that, when $x^2 > a$ and $x < 0$, both terms are positive and strictly increasing as x gets smaller.That's a typo.
 >> Anonymous Sat Nov 16 06:48:38 2019 No.11151632 Are you telling me that when I knock on a SOLID WALL the sound it makes is cause the wall "vibrates"?
 >> Anonymous Sat Nov 16 08:00:44 2019 No.11151710 >>11146370Stupid question here.I am doing binomial theorem problems, but I'm a little confused now.Some of the questions are asking to "state the range of values of x for which the series is convergent" or "state the limits of x for which the expression is valid". I have no idea what's it's asking for and my book doesn't explain it.
 >> Anonymous Sat Nov 16 08:00:50 2019 No.11151712 File: 254 KB, 2048x1151, vorsicht radioaktiv.jpg [View same] [iqdb] [saucenao] [google] [report] Anyone know what this is? A mate found it, belonged to his dad apparently? Dad was German, I think the words translate to Caution Radioactive. It's in a lead-lined box, kinda worried it might be dangerous, but we really want to find out what it is.
 >> Anonymous Sat Nov 16 10:05:12 2019 No.11151849 >>11151712Probably cesium or some shit
 >> Anonymous Sat Nov 16 13:13:34 2019 No.11152187 I'm supposed to find the convergence/divergence of[eqn]\sum _{n=1}^{\infty }\:\frac{2^{n-1}3^{n+1}}{n^n}[/eqn]I think I'm supposed to use the root test, but I'm not sure how to manipulate the numerator so that the 2 and 3 are both just to powers of k.Or does that not matter, and I just take the k out anyway and leave them as 2^0 and 3^2?
 >> Anonymous Sat Nov 16 13:14:36 2019 No.11152189 >>11152187>kmeant to say n. It's k on my paper.
 >> Anonymous Sat Nov 16 13:29:08 2019 No.11152214 >>11149595i didn't know you shitposted out of jp too.
 >> Anonymous Sat Nov 16 13:34:13 2019 No.11152231 >>11152187Pull out the constants to get:[eqn] \frac{3}{2} \sum_{n=1}^\infty \left( \frac{6}{n} \right)^2[/eqn]And note that for sufficiently large* n, the n-th term is dominated by** the geometric series $(1/2)^n$, which converges. So your series converges as well.* I.e. by throwing away finitely many of the initial terms, which has no effect on the convergence/divergence of the sum** I.e. $| (6/n)^n | \leq |(1/2)^n|$.
 >> Anonymous Sat Nov 16 13:38:46 2019 No.11152249 File: 115 KB, 672x700, 1540630402621-min.jpg [View same] [iqdb] [saucenao] [google] [report] >>11152231>squaredPower is n, actually.Unless you were already skipping to the step of taking n>6 and bounding with ^2.
 >> Anonymous Sat Nov 16 13:43:59 2019 No.11152268 >>11152249based
 >> Anonymous Sat Nov 16 14:14:04 2019 No.11152337 >>11152249>Power is n, actually.Whoops you're right, thanks.The correct version (6/n)^n is in the footnote, though it's probably better to err on the side of pedantry for /sqt/.
 >> Anonymous Sat Nov 16 14:30:07 2019 No.11152385 What academic subject teaches you about stuff like exosphere, different types of metals, natural resources, and stuff like this?Is it just "earth science"? How do I learn this?
 >> Anonymous Sat Nov 16 14:37:55 2019 No.11152402 >>11152337To be entirely honest, I corrected you because I was typing up a reply and kept putting ^2 instead of ^n for no comprehensible reason, so I found it weird you did the same.I was going to use the Basel series as a bound, tho.
 >> Anonymous Sat Nov 16 14:52:12 2019 No.11152421 >>11151710bump.I reall don't get why the limit for binomial expressions, (a+x)^n, where a=1 is always -1 < x < 1.
 >> Anonymous Sat Nov 16 15:12:44 2019 No.11152462 File: 21 KB, 608x472, 20191116215737.png [View same] [iqdb] [saucenao] [google] [report] >>11146370Brainlet here. I need to close the sides of a roof of a barn. The sides are two isosceles triangles, and the only data I have from them is their height and base length. See pic related of what I mean. My question is: is the midsegment theorem applied if I only know the height and base? (I know I can apply Pythagora's theorem, but I still don't know the distance of EB or FA) I've always thought yes, but never tested it in real situations, but now since this barn is nowhere near me I can't check if my result for the midsegment is correct.
 >> Anonymous Sat Nov 16 16:16:22 2019 No.11152601 Is there a term related to the idea of "this technology will never exist in this form because something better will come about before it can be created"? Or put another way "why would you do X if being able to do X meant you could do Y, and Y is better than X."
 >> Anonymous Sat Nov 16 16:18:00 2019 No.11152608 >>11152601differential rates of development among potentially substituted future technologies. preemptive obsolescence maybe
 >> Anonymous Sat Nov 16 16:22:17 2019 No.11152621 File: 52 KB, 1433x764, sure thing.png [View same] [iqdb] [saucenao] [google] [report] >>11152532And then you use the cosine rule.
 >> Anonymous Sat Nov 16 16:29:26 2019 No.11152646 >>11152621180-theta*
 >> Anonymous Sat Nov 16 16:35:10 2019 No.11152661 >>11152646Thanks, I'm going blind as a bat.
 >> Anonymous Sat Nov 16 18:32:33 2019 No.11152991 File: 426 KB, 2765x763, 30970868-91F6-40DB-A5EE-EEFF9C6B2715.jpg [View same] [iqdb] [saucenao] [google] [report] we’re doing Laplace transforms in dif eq, did i do this part right? specifically the right side
 >> Anonymous Sat Nov 16 18:56:38 2019 No.11153064 What are the best books I can get in order to learn how a transorbital lobotomy is performed? Hopefully something a non-physician/surgeon could understand.I don't see how an icepick could be inserted without damaging the extraocular muscles.
 >> Anonymous Sat Nov 16 19:33:54 2019 No.11153181 >>11151562I see that the x^2 would be -inf*-inf = sqrt(infinity squared), but would it be an acceptable answer if I put down inf - inf = 0? Isn't that sort of like an indeterminate form them?
 >> Anonymous Sat Nov 16 19:42:09 2019 No.11153221 >>11152991The only thing that's wrong is you seem to have y0=-1 and y0=1 simultaneously
 >> Anonymous Sat Nov 16 19:44:52 2019 No.11153233 >>11153221its supposed to be 1, where do you see the mistake?
 >> Anonymous Sat Nov 16 19:50:08 2019 No.11153253 >>11153233Never mind, i misread. You look good.
 >> Anonymous Sat Nov 16 19:53:09 2019 No.11153263 File: 2.29 MB, 4032x1966, 400E9863-858F-429A-A0E7-AC7A423A0B21.jpg [View same] [iqdb] [saucenao] [google] [report] >>11153253ty anonthis is what i have now. any ideas? its supposed to become the terms in the top right. this is mostly an algebra question
 >> Anonymous Sat Nov 16 20:11:51 2019 No.11153314 >>11153263Split up the numerator so that you have a sum of rational functions and then use partial fraction decomposition
 >> Anonymous Sat Nov 16 20:17:15 2019 No.11153332 >>11153314how do you do partial fractions with a denominator you cant factor?
 >> Anonymous Sat Nov 16 21:01:53 2019 No.11153463 File: 231 KB, 1000x1000, 1573316349847.jpg [View same] [iqdb] [saucenao] [google] [report] >>11153332You dont factor the exponential, you factor the rational function that multiplies it. Then you look at a table of LTs and apply a shifting theorem.>>11151632Walls make sounds because they are not absolutely solid. Only a vibrating wall will move the air around it and make sound.>>11150847Bleach is a solution of NaClO. When you heat the water, the Na ions and ClO ions decompose to something like units of NaCl and NaClO3 according to wikipedia.t. not a chemist>>11152462b/h = AB/(h-CD)>>11149595Gross!
 >> Anonymous Sat Nov 16 21:20:11 2019 No.11153528 >>11151710nice questiom, how into binomial theorem for algebra (just use induction or is here something else?) and more important in calculus? binomial theorem for complex variable?
 >> Anonymous Sat Nov 16 21:21:34 2019 No.11153531 >>11153463>You dont factor the exponential, you factor the rational function that multiplies it.i legitimately do not know what you mean by this
 >> Anonymous Sat Nov 16 21:25:38 2019 No.11153542 File: 46 KB, 571x531, slav.jpg [View same] [iqdb] [saucenao] [google] [report] >>11153528>binomial theorem for complex variable>about to tell anon the binomial theorem works for any commutative ring, even if some of the terms end up vanishing>open wikipedia just in caseWhat the hell, I didn't even know this existed.https://en.wikipedia.org/wiki/Binomial_theorem#Newton's_generalized_binomial_theorem
 >> Anonymous Sat Nov 16 21:29:17 2019 No.11153553 >>11153531You manipulate the RHS of the equation to get a sum of rational functions. One of these terms, however, will have an exponential in the numerator (so it isnt really a rational function, but you know what I mean). You find the inverse LT of that function and use a shifting function (i.e. $\mathcal{L}^{-1}\big(\exp{-as}F(s)\big)=f(t-a)\cdot u(t-a)$
 >> Anonymous Sat Nov 16 21:30:33 2019 No.11153557 >>11153553fucked up the TeX, its obviously supposed to be exp(-as)F(s) inside the inverse LT
 >> Anonymous Sat Nov 16 21:38:15 2019 No.11153572 File: 673 KB, 3622x665, 4D50C59F-7A2E-4EEF-B9F0-1D578C4C9FD5.jpg [View same] [iqdb] [saucenao] [google] [report] >>11153553>>11153557i cant inverse Laplace any of thesedo i have to use partial fractions? i feel like a retard, but i understand how to solve the problem, i just do know how to move the numbers around in the correct way
 >> Anonymous Sat Nov 16 21:41:18 2019 No.11153583 >>11153572>do i have to use partial fractionsYes. It can be tedious, but usually not too bad. Just google how to do PFDs
 >> Anonymous Sat Nov 16 21:47:17 2019 No.11153600 >>11153583>Just google how to do PFDsfrom what im reading, if i cant factor the denominator then my options are limited
 >> Anonymous Sat Nov 16 21:48:32 2019 No.11153603 >>11153600>I can't solve a second degree polynomial by hand
 >> Anonymous Sat Nov 16 21:49:45 2019 No.11153607 >>11153603how would you do it?
 >> Anonymous Sat Nov 16 21:51:52 2019 No.11153610 >>11153607With Baskara.
 >> Anonymous Sat Nov 16 21:54:19 2019 No.11153615 >>11153600You dont understand PDF if you think this is a problem
 >> Anonymous Sat Nov 16 21:55:12 2019 No.11153618 >>11153615thanks for the input
 >> Anonymous Sat Nov 16 21:55:28 2019 No.11153622 >>11153615PFD***
 >> Anonymous Sat Nov 16 21:59:14 2019 No.11153633 >>11153618Hunny, I've held your hand and done everything I can to help you with your HW problem save literally doing it myself. It is time for you to read the text, practice your algebra, and do it yourself. Good luck~!
 >> Anonymous Sat Nov 16 22:05:36 2019 No.11153655 >>11153633its spelt "honey"i asked for help with one step of a very long problem and you certainly tried to help me with it, and i appreciate that, but you really didnt have to dedicate an entire post to telling me i didnt understand something as soon as you decided that you wouldnt/couldnt help me
 >> Anonymous Sat Nov 16 22:08:11 2019 No.11153661 >>11153655>wouldntIm just fucking with you.
 >> Anonymous Sat Nov 16 22:10:19 2019 No.11153670 >>11153655Alright, Im feeling nice. Specifically which term are you having trouble decomposing?
 >> Anonymous Sat Nov 16 22:13:11 2019 No.11153675 Is cocohomology the same as homology?I.e. I have a chain complex so I get homology. I dualize, so I get cohomology. I dualize again, what do I get?
 >> Anonymous Sat Nov 16 22:14:20 2019 No.11153677 >>11153675>dualize>dual>what happens when I do it twice>dualize
 >> Anonymous Sat Nov 16 22:14:44 2019 No.11153679 >>11153670any of the ones with the second degree polynomial 2x^2+x+2 in the denominator (all of them)my (tenuous) understand of PFD is that if the term in the denominator has no factors then you cant do anything. do i have to complete the square or something?
 >> Anonymous Sat Nov 16 22:44:00 2019 No.11153722   File: 291 KB, 640x550, yukari_smile3.png [View same] [iqdb] [saucenao] [google] [report] >>11147127Antimatter are $CT$-partners of matter, where $C$ and $T$ are charge conjugation and time reversal operators, respectively. The reason that $u + u^\dagger \rightarrow 2\gamma$ vertoces are allowed is because you have the the term $\psi^\dagger \not A \psi$ in the QED Lagrangian.Remember, bosons have integer spin, and the Abelian $U(1)$ gauge boson (photon) has spin 0. This means that they transform under trivial representations of $\mathfrak{so}(1,3)$ for which $C$ and $T$ are both the identity.>>11147731In terms of plain relativistic QM, the Heisenberg algebra and its representation Fock space gives the proper setting for us to talk about "particles". For a particle to exist at different times, it must be an excitation of a non-local second-quantized field operator $\psi$ for which $\langle \psi^\dagger(t)\psi(t')\rangle \sim \text{const}$. If this particle is not part of the vacuum (namely if $\psi \not\in P_0$ where $P_0$ is the orthogonal projection onto $\operatorname{ker}H$ with $H$ some Hamiltonian involving $\psi$), then it necessarily violates the Lieb-Robinson bound $\langle[\tau^H_t(\psi),\psi]\rangle \sim \text{const}$, where $\tau_t^H(A) = e^{-iHt}Ae^{iHt}$ is the Heisenberg dynamics generated by $H$. Unless the time direction is compactified to $S^1$ and $t = t' \mod 2\pi$ like in a time crystal, you best have a good reason for violating the Lieb-Robinson bound.>>11149157The adjoint representation is the natural action $h\mapsto ghg^{-1}$ of $G$ on $\mathfrak{g}$. Think of this as the conjugation action on $G$ near the identity; naively it "rotates" the tangent space.
 >> Anonymous Sat Nov 16 22:47:13 2019 No.11153727 >>11153722I meant $\psi\not\in \operatorname{im}P_0$, of course.
 >> Anonymous Sat Nov 16 22:57:57 2019 No.11153741   >>11153679>do i have to complete the square or somethingyeah, turns out you do.[eqn]\frac{1}{2s^2+s+2}=\frac{1/2}{(s+\frac{1}{4})^2+\frac{15}{16}}[/eqn]This is something you should know how to inverse LT.[eqn]\frac{1}{s^2(2s^2+s+2)}=\frac{A}{s}+\frac{B}{s^2}+\frac{Cs+D}{2s^2+s+2}=\ ...\ =-\frac{1/4}{s}+\frac{1/2}{s^2}+\frac{s/2}{2s^2+s+2}-\frac{3/4}{2s^2+s+2}[/eqn]All of this you know how to inverse LT. Think: how would you manipulate the last two terms to being something more similar to the form in the first equation? (Hint: you will end up using the other shifting theorem.)
 >> Anonymous Sat Nov 16 22:59:42 2019 No.11153743 >>11153679>do i have to complete the square or something?yes.[eqn]\frac{1}{2s^2+s+2}=\frac{1/2}{(s+\frac{1}{4})^2+\frac{15}{16}}[/eqn]This is something you should know how to inverse LT.[eqn]\frac{1}{s^2(2s^2+s+2)}=\frac{A}{s}+\frac{B}{s^2}+\frac{Cs+D}{2s^2+s+2}=\ ...\ =-\frac{1/4}{s}+\frac{1/2}{s^2}+\frac{s/2}{2s^2+s+2}-\frac{3/4}{2s^2+s+2}[/eqn]All of this you know how to inverse LT. Think: how would you manipulate the last two terms to being something more similar to the form in the first equation? (Hint: you will end up applying the other shifting theorem.)
 >> Anonymous Sat Nov 16 23:01:08 2019 No.11153748 >>11153743fucking damn. ignore the TeX, all the important bits are readable.
 >> Anonymous Sat Nov 16 23:01:39 2019 No.11153751 >>11153743ty, anon, and double thanks for taking the time to tex it
 >> Anonymous Sat Nov 16 23:04:32 2019 No.11153761
 >> Anonymous Sat Nov 16 23:50:56 2019 No.11153848 File: 1021 KB, 1000x1460, __remilia_scarlet_touhou_drawn_by_maru_chan_niko__1f5fa3c051aac04ea37722598cb6d89c.jpg [View same] [iqdb] [saucenao] [google] [report] >>11149595Scientifically speaking, how stinky would Remilia's unwashed vampire feet be?
 >> Anonymous Sun Nov 17 00:27:06 2019 No.11153892 File: 1.78 MB, 4032x2099, 52DC225D-E74F-4FDE-948D-ECE1815D83A7.jpg [View same] [iqdb] [saucenao] [google] [report] >>11153761heres what i finally got, no clue if its right but i thought you might like to see the fruits of your help c:ty(btw i just assumed your second line of tex was correct without checking it, so i hope it was!)
 >> Anonymous Sun Nov 17 00:55:57 2019 No.11153929 >>11153892im too drunk and can't be assed to go through all the algebra right now but it looks like you're on the right track. if your answer isn't correct, it's because my PFD was bad or because you made some dumb algebra mistake. grats, babe.
 >> Anonymous Sun Nov 17 01:16:02 2019 No.11153972 >>11153929>you made some dumb algebra mistakeit would be a christmas miracle if i didnt desu
 >> Anonymous Sun Nov 17 02:30:21 2019 No.11154126 File: 942 KB, 1920x1080, 1487119239288.png [View same] [iqdb] [saucenao] [google] [report] Reposting from previous threadIs it correct to say that a projective module is a module P such that every morphism onto it from any module has a right inverse that is also a morphism?I'm trying to understand what a projective module is and why it's useful or important. I know the "lifting" definition but I don't get what it's trying to say, and I'm trying to work with its characterizations instead. For example I've seen projective modules be referred to as locally free modules, but I also don't get what's that's supposed mean since having a basis locally doesn't really seem to make too much sense, and I haven't seen someone define that property instead of just mention it (any textbook I should read that has that definition, by the way?). I've also seen the short split sequence "definition" (which we learned as a theorem), that states that a module P is projective iff every short exact sequence $0 \longrightarrow A \longrightarrow B \longrightarrow P \longrightarrow 0$ is split. Now, among all the characterizations of short split sequences, I remember that a short sequence is split iff the morphism from B to P has an inverse morphism to the right, and since that's supposed to happen for any module B, that's where I get my "definition" in the first paragraph, where I try to drop the context of short exact sequences and just mention surjective morphisms in general. Is this idea good enough, then? I'm a bit confused cause it seems like a way simpler form to understand its properties but no one states it like that. Also anyone has a better way to understand the idea of projective modules?
 >> Anonymous Sun Nov 17 02:54:26 2019 No.11154162   File: 266 KB, 428x556, yukari_smile1.png [View same] [iqdb] [saucenao] [google] [report] >>11154126>Is this idea good enough, then?Not quite, you still need the data of $A$ to make the statement that "every morphism $B\rightarrow P$ has an inverse morphism". More precisely, $given$ the morphism $B\xrightarrow{\phi} P$ with $\operatorname{ker}\phi = A$, we have a section $\psi: P\rightarrow B$ such that $\phi\psi = \operatorname{id}_P$. This implies that the section implicitly depends on what $A$ (and hence what $\phi$) is, and the statement about projectivity of $P$ is for $every$ such possible $A$ if you hold $B$ fixed.
 >> Anonymous Sun Nov 17 03:01:54 2019 No.11154170 >>11153722OK Yukarifag, I got a question. What's really going on with the Feynman slash notation? Please explain all the machinery behind $A_{\mu}\mapsto\gamma^{\mu}A_{\mu}$, desu.
 >> Anonymous Sun Nov 17 03:56:07 2019 No.11154271 >>11154162If the morphism from A to B is $f: A \longrightarrow B$, then isn't it just required that $ker ( \phi) = im (f)$? Or you just mean that the kernel is isomorphic to A? Okay so I've been thinking about it for a bit longer, the problem with the property I stated at first is that the condition is way too strong, right? Cause not every epimorphism onto P needs a section, just the ones that have kernels that are images of monomorphisms from A. But at the same time I can't find a case where this wouldn't hold for every epimorphism. For example, if P is projective and the property had to hold for any A in a short exact sequence, then in particular it would have to hold for $0 \longrightarrow ker( \phi) \longrightarrow B \longrightarrow P \longrightarrow 0$, where $\phi : B \longrightarrow P$ could be any arbitrary epimorphism and f is just the identity (mono)morphism. Wouldn't then this exact sequence imply that the property should hold for any arbitrary epimorphism?
 >> Anonymous Sun Nov 17 04:42:19 2019 No.11154323 If you have a higher order even exponent polynomial, can you rewrite say, 5x^4 + 7x + 9 as (5x^2)^2 and then use the quadratic formula?
 >> Anonymous Sun Nov 17 04:43:23 2019 No.11154324
 >> Anonymous Sun Nov 17 06:44:35 2019 No.11154442 File: 108 KB, 850x1200, __remilia_scarlet_touhou_drawn_by_kyouda_suzuka__094b93dfc7287461d632351d1f1ef411.jpg [View same] [iqdb] [saucenao] [google] [report] >>11153848They wouldn't, Sakuya cleans them every day.>>11154126Sort of, you need surjectivity of the morphism to P.Your proof is highly convoluted, have a simple one: Set $id: P \rightarrow P$ and $f: N P$. Because it's surjective, by the definition of projectivity there's a lift to a map $g: P \rightarrow N$ such that the diagram commutes.>>11154323Was that supposed to be 5x^4 +7x^2 + 9?If so, yes. You set y=x^2 and solve the quadratic normally.Otherwise no.>>11154324Hello.
 >> Anonymous Sun Nov 17 06:47:26 2019 No.11154443 >>11154442I fucking knew the surjective arrow would show up wrong. I went to wikipedia and they just had the symbol copied and pasted instead of the Latex, so I thought I'd be cheeky.Hopefully it works now:f: N P
 >> Anonymous Sun Nov 17 07:51:35 2019 No.11154524 >>11154126from wikipedia:A basic motivation of the theory is that projective modules (at least over certain commutative rings) are analogues of vector bundles.
 >> Anonymous Sun Nov 17 12:24:46 2019 No.11155022 So was Einstein a fraud or not?
 >> Anonymous Sun Nov 17 12:43:52 2019 No.11155056 >>11155022How could Einstein possibly be a fraud?
 >> Anonymous Sun Nov 17 12:46:18 2019 No.11155060 How does smell work? e.g. why does rotten food emanate molecules that smell and how do they have energy to travel? Or worn out shoes
 >> Anonymous Sun Nov 17 13:10:28 2019 No.11155125 Can electromagnetic radiation be explained without special relativity?
 >> Anonymous Sun Nov 17 13:21:01 2019 No.11155163 How can i calculate the logarithm of 2 by hand provided i know that lg 5 = 0,699 and lg 6 = 0,778
 >> Anonymous Sun Nov 17 13:21:59 2019 No.11155167 If we make progress in nuclear fusion, doesn't it mean we could theoretically create gold?
 >> Anonymous Sun Nov 17 13:30:46 2019 No.11155189 >>11155163log ab = log a + log blog 10 = log 2 + log 5log 6 is there as bait.>>11155167Nah.
 >> Anonymous Sun Nov 17 13:40:13 2019 No.11155216 >>11155189Why not
 >> Anonymous Sun Nov 17 13:45:46 2019 No.11155228 File: 2 KB, 354x62, diff eq or what.png [View same] [iqdb] [saucenao] [google] [report] Anyone here who can help me with (what I'm assuming) is a differential equation?I haven't solved any of these in 3 or so years and I don't know where to start.P_n-1 is 100 if thats of any interest.
 >> Anonymous Sun Nov 17 13:59:54 2019 No.11155270 >>11154442So it's necessary and sufficient to say that every epimorphism onto P has a section map then? That about just sums the whole concept of projective modules? Sorry if I'm repeating myself but just want to have that 100% certain.And at any rate, how does the lifting property relate to this, then? Sure, I get how it is defined and how it is used to get to the previous statement (which you already showed is kinda trivial anyways), but what is the advantage of defining projective modules like that if the concept is simpler? Or is there a stronger condition that is being implied and I'm missing?
 >> Anonymous Sun Nov 17 14:01:48 2019 No.11155278 >>11155125Yes. Classical electromagnetism is a thing.
 >> Anonymous Sun Nov 17 14:11:58 2019 No.11155303 File: 244 KB, 1080x482, 20191117_160554.jpg [View same] [iqdb] [saucenao] [google] [report] Help, I am not able too figure out where this definition of q comes from (3)The section that explains it says "let A be the set of all positive rationals p, such that p^2 < 2, likewise, let B be the set of all positive rationals p such that p^2 > 2.It's easy to see that in A there is no number greater than every element of the set, and in B there is no number smaller than every element in the set "Then they say that for each p we can associate a q such that : (3)pls help
 >> Anonymous Sun Nov 17 14:20:47 2019 No.11155322 >>11155270Yeah.>why do we define it this wayGolden rule for picking canonical definitions in maths is "which one is it easiest to state and prove all the others from?"I've given you a proof of one way, which is one line, but proving the way back is a bit worse, (essentially, pick a surjective map from a free module F onto P write out the original definition with the projective P, factor it out with F and do some compositions to find a map from P to N such that the diagram commutes. So essentially, you show by hand that a free module is projective and then you argue from diagrams.)
 >> Anonymous Sun Nov 17 15:04:03 2019 No.11155466 >>11154442>They wouldn't, Sakuya cleans them every day.This is simply not true. Remilia's feet have gone 5 centuries without a single wash.
 >> Anonymous Sun Nov 17 15:17:39 2019 No.11155503 Can virtual particles be oscillated to a >=1 energy level?
 >> Anonymous Sun Nov 17 15:20:35 2019 No.11155506 http://tutorial.math.lamar.edu/Solutions/CalcII/TrigSubstitutions/Prob9.aspxon step 3 how does he get 4secX/(4tanX)^4? sorry can't do the math notation thingy
 >> Anonymous Sun Nov 17 15:22:28 2019 No.11155511 File: 660 KB, 1024x1024, __yakumo_yukari_touhou_drawn_by_ker__b4340cd076c2410bf9f67f3edb601647.jpg [View same] [iqdb] [saucenao] [google] [report] >>11154170In general slashed quantities appear in observable scattering amplitudes like $\operatorname{tr}\not p$. Note that the gamma matrices furnishes a spinor representation of $\mathfrak{sp}(1,3)= \operatorname{Isom}\mathbb{M}$, this means that the map $\operatorname{Tr}^\text{Spin} = \operatorname{tr}\gamma \cdot$ is a map that, intuitively, averages over the spin degree of freedom. You can think of $\operatorname{Tr}^\text{Spin}$ as a "supertrace" of sorts.>>11154271>Or you just mean that the kernel is isomorphic to A?Yep. In fact, projective modules are exactly those that enter as a semidirect product factor in a module $B$, at least locally in terms of its generators. As a direct analogy, fibre bundles fit into the exact sequence $0\rightarrow F\rightarrow E\xrightarrow{\pi} B\rightarrow 0$ with $F$ the fibre space, and vector bundles are always locally trivializable with $\pi^{-1}U \cong F \times B$ for $U \subset B$.
 >> Anonymous Sun Nov 17 15:40:28 2019 No.11155568 Let $R = \mathbb{Z} / n \mathbb{Z}$ be a ring. Show that if and only if the nilradical $R_N = (0)$, no squared prime number will divide n.I don't know how I show either direction, can't find the connection.
 >> Anonymous Sun Nov 17 15:42:03 2019 No.11155575 >>11155506nvm I got it after doing the next example which was cleaner
 >> Anonymous Sun Nov 17 16:00:37 2019 No.11155627 >>11155303It's just a convenient construction, it doesn't come from a particular formula or theorem you should know by that point, just from some clever dude's creativity. It's a common construction used for that particular proof (which you'll find basically everywhere else), so they just throw it out. Or rather I guess you can technically obtain that particular construction using some tricks, for example the secant method or some more advanced stuff, but that is not expected for you to know or prove, and you could also construct it from intuition, trial and error, if you wanted to prove that for other values. You may even find another expression that leads to the same conclusion
 >> Anonymous Sun Nov 17 16:17:19 2019 No.11155671 >>11155568Nilradical is the intersection of prime ideals.If no squared prime number divides n, n = p1..pn. Chinese remainder thoerem: Z/nZ = Z/p1Z x ... x Z/pnZ. Prime ideals are of the form (1)x..x(1)x(0)x(1)x...(1). The intersection is 0. Alternatively do it directly. If a^k = 0, Each pi divide a^k, hence each pi divide a, since pi are prime, hence a=0. So nilradical is 0.If a square of a prime p divides n, say p^2 = 0 mod n. Then p is in the nilradical and is nonzero.
 >> Anonymous Sun Nov 17 16:25:08 2019 No.11155701 >11155511>fibre bundles fit into the exact sequence>fibre bundles>topological spaces>exact sequence>exact sequence of topological spacesPlease don't confuse him further.
 >> Anonymous Sun Nov 17 16:26:11 2019 No.11155705 >>11155701The quotation broke for whatever reason, meant for >>11155511
 >> Anonymous Sun Nov 17 16:28:11 2019 No.11155712   >>11155705The reason it broke is because you used two usenet quotes instead of one.
 >> Anonymous Sun Nov 17 16:34:51 2019 No.11155740 >>11155671we haven't had the fact that the "Nilradical is the intersection of prime ideals" yet, so thanks for a direct proof. cheers
 >> Anonymous Sun Nov 17 16:58:02 2019 No.11155821 btw bless the touhou poster(s) for making this thread every time, i don't know why you (singular or plural) put up with this shit every week or so cheers
 >> Anonymous Sun Nov 17 17:11:41 2019 No.11155870 File: 34 KB, 186x146, what_did_i_mean_by_this.png [View same] [iqdb] [saucenao] [google] [report] >>11155701How is it confusing? Exact sequences (fibration, homotopy, relative, Meyer-Vietoris, Gysin, etc.) appear everywhere in algebraic topology. I just used a very elementary example.
 >> Anonymous Sun Nov 17 17:14:58 2019 No.11155883 Could climate change be a alien terraforming program?
 >> Anonymous Sun Nov 17 17:22:57 2019 No.11155914 File: 204 KB, 1100x1375, pretty_girls_004508_032.jpg [View same] [iqdb] [saucenao] [google] [report] Questions about getting into grad school and changing major to statistics>undergrad was in finance>got a decent job and discovered statistics was far more interesting How does getting into graduate school work when you want to change majors like this? Do you have to take undergrad classes or can you potentially skip or test out of them?
 >> Anonymous Sun Nov 17 17:24:28 2019 No.11155919 File: 109 KB, 800x840, 1573491994978.png [View same] [iqdb] [saucenao] [google] [report]
 >> Anonymous Sun Nov 17 17:31:49 2019 No.11155945 >>11153675can anybody answer this?
 >> Anonymous Sun Nov 17 17:39:11 2019 No.11155974 File: 601 KB, 1548x877, yukari_cone.png [View same] [iqdb] [saucenao] [google] [report] >>11153675CW's in $h{\bf Spec}$ are dualizable so using Brown representability all cohomology theories $E^n(X) = [X,\Sigma^n E]$ with $X$ weakly-CW are dualizable. Given a weakly CW-fold, you can use Poincare duality to move between homology and cohomologies.
 >> Anonymous Sun Nov 17 17:44:56 2019 No.11155986 >>11155870Because it's a homology exact sequence, not a topological space exact sequence.Exact sequences of pointed spaces are honestly the absolute stupidest shit.
 >> Anonymous Sun Nov 17 17:51:22 2019 No.11155997 >>11155986It helps to visualize what's going on in a fibration.>absolute stupidest shitThank you for your opinion.
 >> Anonymous Sun Nov 17 17:55:42 2019 No.11156003 >>11155997>It helps to visualize what's going onIt does, but don't call it an exact sequence, call it an intuition or an analogy.
 >> Anonymous Sun Nov 17 18:04:57 2019 No.11156018 >>11155883could you be a retard?
 >> Anonymous Sun Nov 17 18:30:00 2019 No.11156074 Say you had something that let you sit in the air without moving. A floating chair or something. Would the earth eventually move without you? If not, why not? Wouldn’t be suspended in the air mean you’ll always fall at a different spot due to Earth’s rotation?
 >> Anonymous Sun Nov 17 18:32:11 2019 No.11156081 >>11156074Define "not moving." Your velocity is zero with respect to what point in space, exactly?
 >> Anonymous Sun Nov 17 18:49:36 2019 No.11156125 >>11156081Like keeping the thrusters of a jet pack going to keep you up, but not going towards any other direction.
 >> Anonymous Sun Nov 17 18:51:49 2019 No.11156128 >>11156125Then you would hover over the same spot on the earth because you have the same initial angular velocitu about the center of mass of the earth as the earth does.
 >> Anonymous Sun Nov 17 18:57:39 2019 No.11156138 >>11156128Where does the angular velocity come from?
 >> Anonymous Sun Nov 17 19:00:48 2019 No.11156149 >>11156138the rotation of the earth
 >> Anonymous Sun Nov 17 19:10:07 2019 No.11156173 >>11146370What is a good introductory book into real analysis for self learning and where can I find a pdf?
 >> Anonymous Sun Nov 17 20:41:09 2019 No.11156400 >>11155627Thank you
 >> Anonymous Sun Nov 17 20:41:47 2019 No.11156403 File: 7 KB, 431x60, 2.jpg [View same] [iqdb] [saucenao] [google] [report] can someone check if it's correct?"There is a real number a, so for every integer b the result of the amount of a - b is a rational number.">answer, pic related
 >> Anonymous Sun Nov 17 20:42:04 2019 No.11156404 Is this a good introductory AI course?https://artint.info/2e/html/ArtInt2e.htmlI feel like reading about AI since we didnt have a course about it in university and I dont wanna miss out
 >> Anonymous Sun Nov 17 20:46:57 2019 No.11156417 >>11156403i got confused and put Z instead of Q, i thought Z was rational numbers not Q
 >> Anonymous Sun Nov 17 20:55:45 2019 No.11156428 >>11156403I would turn the colon into a comma. Also you need to say that b is an element of Z.
 >> Anonymous Sun Nov 17 21:00:15 2019 No.11156438 >>11156428thanks
 >> Anonymous Sun Nov 17 21:03:20 2019 No.11156447 File: 24 KB, 694x67, 1.png [View same] [iqdb] [saucenao] [google] [report] So I need to take a mapping modulo p here and show that this has infinitely many a that works. I cannot use any other method, i.e. eisenstein. Completely lost how to do this.
 >> Anonymous Sun Nov 17 21:08:32 2019 No.11156459 File: 7 KB, 513x41, 3.jpg [View same] [iqdb] [saucenao] [google] [report] >>11156428can you check if this is correct?"Each complex number is of the form z = w + i · v with two real numbers w, v."
 >> Anonymous Sun Nov 17 21:30:03 2019 No.11156507 File: 31 KB, 621x440, 4.jpg [View same] [iqdb] [saucenao] [google] [report] i've done the negation, idk it's correct but i also have to do the simplification which i can't
 >> Anonymous Sun Nov 17 21:50:18 2019 No.11156546 >>11156447Why can't you use Eisenstein criterion? Let $a = 3p$ where $p$ is a prime bigger than 5. Then 3 divides 15, 3 divides -30 and 3 divides 3p, but 9 does not divide 3p. Ergo infinite solutions.
 >> Anonymous Sun Nov 17 21:59:35 2019 No.11156571 File: 40 KB, 387x348, swirls.jpg [View same] [iqdb] [saucenao] [google] [report] What are the fluid-dynamic differences between a converging-end and open-end swirl injector?
 >> Anonymous Sun Nov 17 22:28:56 2019 No.11156625 >>11156459What you wrote there would most likely be read by most people as "For all complex z=w+vi, where w,v are real numbers" (also you should probably drop the paranthesis, it looks like you are writing them as an ordered pair in which case they are in $\mathbb{R}^{2}$ and not the real line)From what I understand you are more intfor every z, whereas in your statement it just sounds as if you're picking the complex z's that can have that form, but not stating that that is precisely every complex number z. I could rephrase that statement as "For each complex number z there exist real values of v,w such that z = w+iv", in which case you'd write it as $\forall z \in \mathbb{C} , \exists w,v \in \mathbb{R} : z = w+iv$.>>11156507Also I'm a bit confused about your usage of $\ni$. It is supposed to represent set inclusion but just written in the opposite direction, so something like $\mathbb{R} \ni \forall b \in \mathbb{Z}$ is hard to read, let alone find a meaning for. Or what did you intend to write? I assume that you meant to say that since b is an integer then it is also a real number, but that is not necessary to mention and even if you wanted to do so you could just write $\forall b \in \mathbb{Z} \subset \mathbb{R}$ (ignoring the details about the construction of both sets and other formal stuff).For the negation, it's just a matter of negating the quantifiers first (so basically "exists" becomes "for all" and viceversa), and then negating the predicates, which isn't too hard since if you talk about inclusion then the negation is just not being included, and if you talk about equality then the negation is just an inequality.
 >> Anonymous Sun Nov 17 22:30:22 2019 No.11156627 >>11156625>From what I understand you are more intfor every zAccidentally deleted something when trying to rephrase it. I meant "From what I understand you are more interested in the existence of w and v for every z"
 >> Anonymous Sun Nov 17 23:59:02 2019 No.11156782 File: 111 KB, 968x758, brainlet.jpg [View same] [iqdb] [saucenao] [google] [report] >>11154442Can you explain the quadratic formula thing more? So if you have an equation that has an even root and could be rewritten as say (x^3)^2, do you then have to have the next term as a x^2 and then a constant to make the typical ax^2+bx+c. I don't quite understand why the second term can be squared other than what you said about defining y as x^2....so I guess instead of solving for x you do everything the same way, but the answer is x^2. Is this correct?
 >> Anonymous Mon Nov 18 00:14:01 2019 No.11156808 File: 47 KB, 800x628, 72c6a913bb4866a6af600d16766a5eb2.jpg [View same] [iqdb] [saucenao] [google] [report] >>11156571I know very little about this desu but "Theory and Practice of Swirl Atomizers" by Yuriy Khavkin seems to be a source for pretty much everything you need to knowhttps://books.google.com/books?id=3tqWpzXLVzAC&printsec=frontcover&source=gbs_ge_summary_r&cad=0#v=onepage&q&f=falsegood luck on finding a full copy online>pg 22>for "very open" atomizers with short nozzles, the transition of Fr<1 to Fr>1 takes place without hydraulic jump>nozzle => hydraulic jump>>11156782remilia-anon is saying that for any polynomial $ax^{2n}+bx^{n}+c=0$ you can find the roots by simply letting $y=x^n$ and applying the quadratic formula for y. I kinda don't understand specifically what you are asking lmao.>>11155919>attach some image to bring attention to the post
 >> Anonymous Mon Nov 18 03:09:54 2019 No.11157119 >>11155322Thanks, this helped a lot since at least I kinda know what I'm doing now with the formal definition
 >> Anonymous Mon Nov 18 05:54:23 2019 No.11157276 >>11156782>I don't quite understand why the second term can be squared It usually can't, but when it's of the form ax^2n+bx^n+c it can, you set y=x^n, as bunnyposter pointed out.>you do everything the same way, but the answer is x^2Yeah, if you've swapped y=x^2 and you solve for the roots of y, you then need to take the square roots of those roots to find the solutions to the original problem. Same thing for n-th roots.>>11156808>I kinda don't understand specifically what you are asking lmao.Me neither, I've been wildly guessing since the first reply.
 >> Anonymous Mon Nov 18 06:55:34 2019 No.11157324 File: 317 KB, 473x357, 1560786054873.png [View same] [iqdb] [saucenao] [google] [report] In Latex, is there a way to disable all floating / remove glue stretch+shrink from the entire document?In word documents, I have everything exactly where I want it to be. Latex however tries to be fancy and stretch every page without break into full size. But some pages due to large figures that follow are half empty. Then Latex stretches this half page onto the full page and it looks awful.I just want Latex to act normally without this stupid floaty shit causing different spacing for every single page. Google was useless.
 >> Anonymous Mon Nov 18 08:13:59 2019 No.11157409 >>11156625>Also I'm a bit confused about your usage of ∋It means "such that" in this case
 >> Anonymous Mon Nov 18 08:24:48 2019 No.11157419 Let's say you've got a ring homomorphism from the ring of all complex polynomials in x to the ring of 3x3 matrices with complex coefficients. It is defined by h(x) = A, where A is some matrix in the codomain.How do you know that you can define the homomorphism by just this one mapping? I thought you could only do that if x generates the entire ring (if I remember right, that was true for groups), but I don't see how that could be the case here. I haven't read about ideals yet so if that is essential to understanding the situation please let me know. Thank you anons.
 >> Anonymous Mon Nov 18 08:29:59 2019 No.11157425 >>11157419It's true that x alone doesn't generate the whole ring by itself, but x together with 1 does, and 1 is locked onto the identity matrix.
 >> Anonymous Mon Nov 18 08:45:41 2019 No.11157446 >>11157419>ring homomorphismAre you sure it isn't an algebra homomorphism, or a linear ring homomorphism?>>11157425I don't think that works for ring homomorphisms, since you can just lift complex conjugation to an automorphism of C[x] (pointwise conjugation) and obtain a second homomorphism that still maps x to A.I think, might be wrong. Conjugation was an automorphism of C[x] , wasn't it?
 >> Anonymous Mon Nov 18 08:52:10 2019 No.11157456 >>11157446There's nothing to "work". Many authors (who choose to work with unital rings) take as part of their definition that the multiplicative identity is preserved:https://en.wikipedia.org/wiki/Ring_homomorphismAdmittedly I'm assuming that this is what anon's book is doing, but that's the only way this question makes any sense, since otherwise there are of course multiple homomorphisms that send x to the same matrix.
 >> Anonymous Mon Nov 18 08:55:24 2019 No.11157462 >>11157456>identity to the identityThat's not what I'm talking about, I'm saying that I recalls conjugation of coefficients fixing x and being a ring automorphism (which fixes the identity, obviously) of C[x] to itself, which would mean we have at least two ring homomorphisms which satisfy what anon said, that is, mapping h(x)=A.
 >> Anonymous Mon Nov 18 09:01:37 2019 No.11157472 >>11156507I see three problems in your negation of (a). First, negations are evaluated before subtraction and set inclusion, so you need to have parentheses around a - b ∈ R. You do want to negate the entire expression, right? In fact, ~a doesn't even have a well defined meaning, because a is a number, not a proposition.Second, recall that when you're negating a logical statement you should change ALL the quantifiers, not just the first one. Lastly (and this is a more subtle point but it's still very important), you should switch ∋ and the comma. Why? Think about what you'd be saying if you don't:"For all a in R such that there exists b in Z, a - b is not in Q."This is complete nonsense. How the hell does the existence of some element in Z depend on an an element in R? I don't even know what that question is asking, and you shouldn't either. Now consider this sentence:"For all a in R, there exists b in Z such that a - b is not in Q."Spend as much time as you need until you grasp intuitively why is this is the negation you're looking for. You don't seem to have much intuition for how to phrase statements in logical notation. I highly recommend (for the time being) that you write out the negations in English first, then translate from there, because right now you seem to be blindly following formalistic rules (and not particularly well-formed rules, either); try to keep in mind the sense of what you're ultimately aiming to say. It may also be helpful to examine actual numerical examples: literally try to find a real number such that blah blah blah... it should help you get a clearer idea of what the proposition means.Your original statement of (b) is all screwed up so I'm not even going to comment on the negation.
 >> Anonymous Mon Nov 18 09:20:40 2019 No.11157504 File: 39 KB, 896x212, 2019-11-18.png [View same] [iqdb] [saucenao] [google] [report] >>11157425>>11157446>>11157456Here is the actual statement of the problem. We haven't discussed algebra or linear ring homomorphisms, as far as I'm aware, but then again I usually can't tell what's going on in class. I believe we defined our rings so that they always have an identity element. Could I hear more about how x and 1 generate the ring? For some reason I can't even locate a section about ring generators in Artin or D&F (we don't have an official textbook). Right now it looks to me like they would generate all polynomials with integer coefficients, but not complex.
 >> Anonymous Mon Nov 18 09:27:59 2019 No.11157517 >>11157504Ok I think I will go learn about ideals now.
 >> Anonymous Mon Nov 18 09:42:13 2019 No.11157543 >all polynomials with integer coefficientsRational coefficients, actually.
 >> Anonymous Mon Nov 18 10:03:31 2019 No.11157574 >>11156546because we haven't "learned" it yet, so we cannot use it for our HW
 >> Anonymous Mon Nov 18 10:07:24 2019 No.11157579 >>11146463Read the sticky!
 >> Anonymous Mon Nov 18 10:25:14 2019 No.11157593 >>11156808>I know very little about this desu but "Theory and Practice of Swirl Atomizers" by Yuriy Khavkin seems to be a source for pretty much everything you need to knowThanks!
 >> Anonymous Mon Nov 18 10:35:39 2019 No.11157607 so I'm doing calc 2 for computer science prerequisites at my universitycan someone just explain to me what the FUCK is the point of finding the integral of some random gay ass functionlike I look at the graph of these things and I don't think anything in the real world can be represented by these so what's the fucking point?
 >> Anonymous Mon Nov 18 10:36:57 2019 No.11157609 >>11157607To be able solve differential equations later on.
 >> Anonymous Mon Nov 18 10:39:07 2019 No.11157612 >>11157607>can someone just explain to me what the FUCK is the point of finding the integral of some random gay ass functionThere unironically isn't. Sometimes it is useful to find anti-derivatives when deriving formula from first principles, but basically never is it something more than integrating a sinusoidal function or an exponential.Being very very good at solving arbitrary rational functions is essentially a useless skill. They make you do it in calc II to weed out the super brainlets.
 >> Anonymous Mon Nov 18 10:54:07 2019 No.11157634 File: 79 KB, 1700x680, 983274234.png [View same] [iqdb] [saucenao] [google] [report] I have been working on a model similar to the newton cradle and other "kinetic art" that has an interesting science/physics attraction and because it has science/physics involved I thought /sci/ might be the place to post about itThe version I have now is made of drinking straws, small ball bearings, and neodymium magnets from ebay and some from old hard drives. I was planning on building a larger model using PVC pipe, larger ball bearings, and either large neodymium or just stacking them together. The way the small model works is similar to how I hope the large model will work except just bigger. With the small model the steel balls role around the track from start to finish about 5 or 6 times with the max being the occasional 8 or 9. The larger bearings I already have seem to travel smoother in PVC pipe than the drinking straws I am using on the smaller modelMy question is do you think a single larger neodymium magnet and many smaller neodymium magnets would have a similar magnetic field? If multiple magnets would have a similar magnetic field maybe have the ability to adjust magnetic fields by swapping around magnets could allow for finer adjustment>copy and paste "Thanks in advance." to the end of the post"Thanks in advance."
 >> Anonymous Mon Nov 18 10:55:43 2019 No.11157638 >>11157607PID control. Think of a thermostat. To turn the furnace on or off, you could:Proportion: Apply some proportion to the current signalIntegral: Evaluate all the past signalsDerivation: Try to predict to the future by focusing into the current signal's highest resolution possible.Also derivation of laws. You have - integral formation: Different equation for a range of inputs- regular equation: all inputs, some inputs may output infinities- derivative formulation: works for all inputs, no sharp corners
 >> Anonymous Mon Nov 18 10:57:04 2019 No.11157640 >>11157634Im not sure if magnets are a good way to get the bearing up that incline.
 >> Anonymous Mon Nov 18 11:02:07 2019 No.11157652 File: 3 KB, 320x254, 1.png [View same] [iqdb] [saucenao] [google] [report] >>11146370Where the hell does the 1 come from?
 >> Anonymous Mon Nov 18 11:02:08 2019 No.11157653 >>11157607Integrals are mostly used to solve PDE's and ODE's once you graduate, and you will need to know how to solve ODE's and PDE's if you have any hope of a career in Science. Pretty sure CS will need to know these as well, especially if you plan to work with programming engines.I have graduate friends and they say PDE's and ODE's are the biggest chunk of their work.
 >> Anonymous Mon Nov 18 11:05:58 2019 No.11157664 >>11157640It works on the smaller model. The distance between the bottom and top of the ramp decreases and the bearings travel upward to the top of the ramp. On the small model the bearings overshoot the ramp enough that with molded plastic ridge and a part where the bearing hits the to of the straw is enough to knock the bearing free of the magnets pull and continues rollingRollin upwards is not the problem but finding the exact point where the magnetic force is enough to pull upwards but also just right to let go is key. I used a piece of steel to finely tune the magnetic attraction and that was the key on the smaller version. If or when I build the larger version is whether or not a single large magnet or multiple smaller magnets will workPut a steel bearing in a plastic pipe next to a strong neodymium style magnet and the ball will travel vertical in an attempt to get closer to the magnet and it does it with speed
 >> Anonymous Mon Nov 18 11:09:51 2019 No.11157669 >>11157652Any number divided by itself (except for zero) is 1.
 >> Anonymous Mon Nov 18 11:13:56 2019 No.11157671 >>11157652Wait why is the original expression supposed to equal zero? Otherwise the solution doesn't make sense.
 >> Anonymous Mon Nov 18 11:19:14 2019 No.11157676 >>11157607if your function is a rate you can integrate it to find a valueexamples:function is velocity (distance/unit time) -> integrate to find the total distance between two timesfunction is a probability density (probability/unit something) -> integrate it to find the total probabilityfunction is a physical density (mass per unit space or number of things per unit space or whatever) -> integrate it to find the total mass or number of thingsfor cs you can probably get away with - knowing it's sort of the inverse of differentiating- knowing you're basically summing the area under the curve- knowing about newton's method and some extensions to it as that's the building blocks of numerical integration methods- knowing what differential equations are because modelling them is a huge part of what high performance computing actually gets doneyou need the rest of it to pass the course though lmao
 >> Anonymous Mon Nov 18 14:36:53 2019 No.11158090 File: 192 KB, 1883x1299, IMG_20191118_203241.jpg [View same] [iqdb] [saucenao] [google] [report] idk if im retarded or what, i didnt touch graph theory for a long time, but shouldn't K 1,1,1 be just a triangle? unless K doesn't mean a complete partite graph as i rememberthis is what the book im reading now shows K 1,1,1 as
 >> Anonymous Mon Nov 18 16:19:52 2019 No.11158367 >>11157543So what gives? Is this not a properly defined homomorphism then?
 >> Anonymous Mon Nov 18 16:25:33 2019 No.11158378 File: 91 KB, 531x601, cccccccccccccccccccccccccccccccccccccccc.png [View same] [iqdb] [saucenao] [google] [report] I'm confused with magnetic torque.For (a) and (b), the magnetic moment would be pointing towards me/away from me. For (a), using the right hand rule, my thumb representing the magnetic moment, is pointing towards me. My index finger (B-field) points to my left, so the rest of my fingers point straight down. Since the torque would be perpendicular to the axis of rotation, there would be no net torque, right? Same with (b)?But then, looking at (c), the B-field and the magnetic moment would be in the same direction, making their cross product be 0... meaning no net torque. Obviously one of these is wrong.
 >> Anonymous Mon Nov 18 16:55:18 2019 No.11158450 can somebody who studied their respective field tell me what is the most difficult branch of mathematics, physics, biology and chemistry?
 >> Anonymous Mon Nov 18 17:34:20 2019 No.11158569 >>11158378For (a), the magnetic moment points into the page, meaning the torque points up within the plane of the page
 >> Anonymous Mon Nov 18 17:49:14 2019 No.11158609 File: 7 KB, 589x100, 1.png [View same] [iqdb] [saucenao] [google] [report] >>11146370Am I retarded or should the answer here be 4.981... x 10^-5
 >> Anonymous Mon Nov 18 18:19:08 2019 No.11158672 >>11158569That's what I thought (just opposite signs) so I'm confused as to how the thing can even rotate
 >> Anonymous Mon Nov 18 18:25:47 2019 No.11158684 >>11152462similar triangles. DE is half the base. GD is given. GC is 2.5-0.6. Now you can find CB by setting up the proportions. Then multiply it by 2 to get AB
 >> Anonymous Mon Nov 18 18:26:23 2019 No.11158685 File: 189 KB, 512x512, Ce69OO2XIAEwKdH.png [View same] [iqdb] [saucenao] [google] [report] >>11158672Magnetic moments aside, you know that in (a) the current in the loop makes a magnetic FIELD that goes into the page by RHR. Magnetic fields want to align with each other, so the torque is CCW. (b) is obviously CW by same logic. For (c) the field made by the current is parallel to external field, so no torque.>>11158450[My field]
 >> Anonymous Mon Nov 18 18:29:41 2019 No.11158695 File: 1.17 MB, 884x1137, __remilia_scarlet_touhou_drawn_by_yuki_popopo__aa7e67619508fef8151d02ba480cf9a6.png [View same] [iqdb] [saucenao] [google] [report] >>11158367Yeah, I think so.Either way, they probably want the map that sends constant a to matrix aI.I think the answer is something like the ideal generated by the matrix's characteristic polynomial.>>11158450>mathsProbably PDEs, to be entirely honest.I think just about half of the problems in differential geometry and topology can be turned into existence and smoothness of PDEs, but that just makes shit harder to solve.
 >> Anonymous Mon Nov 18 18:29:45 2019 No.11158697 Are "brain trainer" apps a meme? I'm just looking for nice puzzle games on Android that aren't completely brain-dead like Candy Crush or something.
 >> Anonymous Mon Nov 18 18:33:27 2019 No.11158709 >>11158697sudoku
 >> Anonymous Mon Nov 18 18:38:26 2019 No.11158722 >>11158695>PDEsDifferential equations in general is a fucking mess of a field. Also, external flow theory in fluid mech. t. ME
 >> Anonymous Mon Nov 18 19:11:47 2019 No.11158787 >>11158722>Differential equations in general is a fucking mess of a field.mind going into more detail? What makes that so, from your point of view?
 >> Anonymous Mon Nov 18 19:56:04 2019 No.11158889 >>11158787There is no general theory to solve arbitrary PDEs.At some point, a lot of PDEs need their own methods and theory to tackle. The entire subject just feels a bit disconnected and unorganised
 >> Anonymous Mon Nov 18 19:58:09 2019 No.11158897 >>11158787This guy >>11158889 isnt me, but basically what he said. Differential equations is disgusting as compared to, say, algebra or complex analysis.
 >> Anonymous Mon Nov 18 21:43:34 2019 No.11159140 >>11158787>>11158889>>11158897don’t worry fellas, i just looked up the Navier-Stokes problem and it doesn’t look so bad. expect a revolution in the field by 2025.
 >> Anonymous Mon Nov 18 21:48:07 2019 No.11159147 >>11146370Mathematically speaking, if 88 < 100 why are blacks still considered human?
 >> Anonymous Mon Nov 18 21:50:16 2019 No.11159152 >>11159147because IQs are only comparable between members of the same species.
 >> Anonymous Mon Nov 18 21:52:14 2019 No.11159158 >>11159152But that one ape had an IQ of 66. Comparable to the IQ of an African child.
 >> Anonymous Mon Nov 18 21:52:52 2019 No.11159160 >>11159147because 10>5.5white boi
 >> Anonymous Mon Nov 18 21:54:49 2019 No.11159168 >>11159158yeah apes are close enoughnow that i think about it blacks may be the missing link after all
 >> Anonymous Mon Nov 18 21:55:15 2019 No.11159170 File: 245 KB, 1161x1280, 1573480660519.jpg [View same] [iqdb] [saucenao] [google] [report] >>11159160>muh dicktypical
 >> Anonymous Mon Nov 18 21:55:55 2019 No.11159172 >>11159147>>11159152>>11159158>>11159160>>11159168>>11159170not the thread for this. please leave.
 >> Anonymous Mon Nov 18 21:56:50 2019 No.11159177 >>11159172Sorry, please direct me to the nearest appropriate thread.
 >> Anonymous Mon Nov 18 21:59:54 2019 No.11159188 >>11159177/pol/.
 >> Anonymous Mon Nov 18 22:00:05 2019 No.11159189 >>11158897>>11158889I've been aware that they're difficult/well-nigh impossible to solve, but trying to google "why is it difficult to a the solution to a differential equation" only brings up people looking for homework helpI wish I could find actual literature on this kind of stuff so I could learn about it more
 >> Anonymous Mon Nov 18 22:03:07 2019 No.11159197 >>11159189it's literally not. Don't fall for the autistic mathematician circlejerkers meme. You literally just treat dx/dy as a fraction and rearrange. Problem solved. It's only hard if you have extreme autism like all the mathematicians. Adopt an engineering mindset and it will set you free.
 >> Anonymous Mon Nov 18 22:06:01 2019 No.11159208 >>11159197I don't mean for random well-behaved cut-and-dry ODE/PDEs they give in textbooks that are guaranteed to have solutions, I mean for the gnarly ones that you find working in the wild that don't have any pretty algorithm found in a textbook to solveWhy are those difficult? How did the progenitors of calculus go about solving them by hand long before we had numerical methods, or even computers? Shit like that
 >> Anonymous Mon Nov 18 22:11:46 2019 No.11159219 >>11159197>You literally just treat dx/dy as a fraction and rearrangethis doesn't work if you are working with partials or an order higher than 1
 >> Anonymous Mon Nov 18 22:31:04 2019 No.11159258 >>11159219Source?
 >> Anonymous Mon Nov 18 22:39:59 2019 No.11159265 So, I'm really bad with statistics. Can't remember how to do real easy shit, and can't figure out how to Google what I need. My problem is something like this:20% of the components for a project are capacitors.I have a shitty supplier, so the capacitors are twice as likely to fail as the other components. Assume the other components are equally likely to fail.What percentage of my failed components are failed capacitors?Can I do this?Given that they are twice as likely to fail, can I just double their number and divide by the new total: that is, as 20 of 100 components are capacitors, so 40 of 120 components are failed capacitors, so 1/3 of my components are failed capacitors?
 >> Anonymous Mon Nov 18 22:40:50 2019 No.11159268   >>11159258solve $\frac{\text{d}^2x}{\text{d}t}+x=0$ while treating the second derivative as a fraction.
 >> Anonymous Mon Nov 18 22:41:53 2019 No.11159269 >>11159258solve $\frac{\text{d}^2x}{\text{d}t^2}+x=0$ while treating the second derivative as a fraction
 >> Anonymous Mon Nov 18 22:53:09 2019 No.11159299 >>11158378>perpendicular to the axis of rotationyou _just_ said the torque is up or down in the same damn sentence do you know what perpendicular means?
 >> Anonymous Mon Nov 18 22:54:46 2019 No.11159305 Work out the percentage for everything and then work out what the question is asking. Statistics is honestly so easy. You're asking what percentage of failed components are capacitors so you need to know the ratio of capacitors and ratio of fail rate which you know. 2:8 * 2:1 = 4:8 = 1/3
 >> Anonymous Mon Nov 18 23:02:12 2019 No.11159332 File: 16 KB, 241x209, umd.jpg [View same] [iqdb] [saucenao] [google] [report] Can someone help me intuitively understand this "Mean Value Proposition"? Its statement is as follows:$Let \textbf{x} be a point in \mathbb{R}^n and let \mathit{r} be a positive numer. Suppose that the function \mathit{f}: B_r(\textbf{x}) \to \mathbb{R} has first-order partial derivatives. Then if the point \textbf{x} + \textbf{h} belongs to B_r(\textbf{x}), there are points \textbf{z}_1, \textbf{z}_2, ... , \textbf{z}_n in B_r(\textbf{x}) such that:\mathit{f}(\textbf{x} + \textbf{h}) - \mathit{f}(\textbf{x}) = \sum_{i=1}^{n} h_i \frac{\partial f}{\partial x_i}(\textbf{z}_i)and||\textbf{x} - \textbf{z}_i|| < ||\textbf{h}|| for each index \mathit{i} with 1 <= \mathit{i} <= n$I grok what it means but I can't really visualize it not reason through it.Thank you!
 >> Anonymous Mon Nov 18 23:04:09 2019 No.11159346 >>11159332Same content but reformatted (new to LaTeX)Let \textbf{x} be a point in \mathbb{R}^n and let \mathit{r} be a positive numer. Suppose that the function \mathit{f}: B_r(\textbf{x}) \to \mathbb{R} has first-order partial derivatives. Then if the point \textbf{x} + \textbf{h} belongs to B_r(\textbf{x}), there are points \textbf{z}_1, \textbf{z}_2, ... , \textbf{z}_n in B_r(\textbf{x}) such that:$\mathit{f}(\textbf{x} + \textbf{h}) - \mathit{f}(\textbf{x}) = \sum_{i=1}^{n} h_i \frac{\partial f}{\partial x_i}(\textbf{z}_i)$and||\textbf{x} - \textbf{z}_i|| < ||\textbf{h}|| for each index \mathit{i} with 1 <= \mathit{i} <= n
 >> Anonymous Mon Nov 18 23:06:36 2019 No.11159361 >>11159305It looks like it comes to the same results. Given the math, that makes sense. Thanks anon.
 >> Anonymous Mon Nov 18 23:07:33 2019 No.11159365 File: 31 KB, 865x323, fuck.png [View same] [iqdb] [saucenao] [google] [report] >>11159346Fucking dammit, here it is
 >> Anonymous Tue Nov 19 04:27:35 2019 No.11159872 Is it true that if p(x) | q(x), then any root of p should also be a root of q?
 >> Anonymous Tue Nov 19 08:32:46 2019 No.11160179 >>11159872You can write q(x) as p(x)*r(x) for some polynomial r(x). When is this equal to zero?
 >> Anonymous Tue Nov 19 11:48:34 2019 No.11160575 >>11159269I mean eveny' = y + xcannot be solved by "literally just treat dx/dy as a fraction and rearrange"
 >> Anonymous Tue Nov 19 16:16:04 2019 No.11161295 if we square adjacency matrix Gi,j shows how many paths of length 2 are there, right?does it work the same way for cubed and paths of length 3? if yes, does it go indefinitely?
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