/sci/ - Science & Math

I want to learn more math than HS crap but my job takes up all of my time that isn't spent sleeping. I need it to pay my rent and assloads of debt and can't find anything that has better pay or hours.

>tfw too retarded for HS physics
I'm not gonna make it.

>>10985230
>finally got my shit together and enrolled in Uni again
>met my former classmate that I was on pretty good terms with
>he’s treating me like a friend (because he doesn’t know anybody else)
>have a study partner and friend for the first time in my life
>we prepare and practice math together
>maintaining motivation and discipline is infinitely easier with a friend
>everything is going great
>I might actually have a chance at making it this time
>actual courses commence
>still can’t solve simple math problems without hours of pondering and plenty of nudges from smarter people
>realize I’m forever doomed to be a brainlet and no amount of studying or companionship is gonna remedy that
>tfw I fell for the meme

don’t do math, kids. it’s harmful.

>applying for math/stats
>basically 0 math skills
Shouldn't be too hard

Riddle me this dummies:

>Two cars are driving directly towards one another on a straight road
>they are exactly 5000m away from one another.
>The one at 0m is driving 80m/s
>the one at 5000m is driving 95m/s.
At what distance do the two cars pass one another?

How much IQs do need to understand topology?

>>10986179
Use klause Janich Topology

>>10985230
Build Math guide from this curriculum using more friendly for self taught books.

>>10986172
They wouldn’t pass eachother. They’d collide because they’re driving towards eachother lmao

>>10986213
That's even retarded from a lateral thinking standpoint. I award you no points and may God have mercy on your soul.

>>10986172
2500m

>>10986227
they are going at different speeds. That's the puzzle.

>>10986172
2968.75 and 2031.25 respectively

>>10986304
RRRRN Wrong!

>>10986172
2105.26 and 2894.74

>>10986395
Wrong again. I'd be curious how you guys are getting these numbers.

>>10986172
at roughly 2285.714 m

>>10986421
First I figured what proportion of the greater speed was the difference between the two then I figured that proportion would equal the difference in the distance/2 the two cars traveled.

>>10985230
Yes, hello, this post describes me.

I'm currently studying electronic engineering and I'm two weeks into my first year. It's been four years since I've done any maths.

We're starting off with indices lmao. But the only ones I struggle with are fractions where a the numerator or denominator is raised to a fraction. e.g.

3/4^2/4

Wtf do I do there?

>>10986441
not the most baseless methodology I suppose

>>10986442
3/4^2/4= 3/4^1/2= sqrt(3/4)

>>10986213

>>10986455
okay so what if it was 3/4^5/7? would that be 7throot(3/4^5)?

>>10986424
>>10986421

I first searched for the time they would pass each other:
95x + 80x = 5000
x = 5000/175

Then I simply had to calculate the distance by multiplying the speed of the car at the 0m mark with the time he needed to pass the other car
80 * (5000/175) = 2285.714...

>>10986485
yes

>>10986492
yeah that's right. Lots of people know how to do these. I'm wondering the methods the brainlets used, like >>10986441

>>10986501
Oooh i think it was the same anon
>>10986395
>>10986304
He at first did
((95/80) * 5000)/2
then
((80/95) * 5000)/2

Is x^2/x equal to x?

>>10986643
Yes except when x=0

>>10986643
x^(2/x)
(x^2)/x

One is equal to x (except for 0), the other is not. which one is right ?

>>10986643
Yes because that's the same as saying x^2/x^1. So you get x^1.

What is the best way to learn math so that I dont Forget the shit after 1 week?

>>10985704
spending hours of pondering to understand problems is how you get better. you don't care that much about learning math if knowing someone smarter than you can figure it out faster is enough to ruin you. i don't know any undergraduate math program that requires content you need strokes of genius to handle. and i know your not in a crazy difficult program. you CAN brute force your way through to straight A's and an excellent understanding of the material with sheer effort.

>>10987522
Build on what you learn so that you're forced to apply the basic stuff and so gain more and more practice with it. This is what most maths courses and textbooks try to do because it works.

>>10985230
/mlg/ is machine learning general, take your brainlet bullshit elsewhere

>>10987580
>machine learning General
Thats /g/ stuff

>>10986213
LMAO EINSTEIN'D

>>10986172
I made this way more difficult than it had to be

95m/s/80m/s = 1.1875
2500/1.1875 = 2105.263
2500-2105.263=394.737
394.737/2=197.368
197.368/1.1875=166.205
197.368-166.205=31.163
31.163/2=15.582
.....
1.230/1.1875=1.036
1.230-1.036=0.194 (the difference is now negligible)

2500+197.369+15.582+1.230= 2714.180274

I guess in calculus you probably learn how to turn this into a single equation accounting for the infinite case. Anyway, that's what I figured out starting from 0 and I'm proud of myself.

Broos, is math supposed to make sense instantaneously, like your mother's tongue, or does even 200 IQ person have to think much before stating something or seeing a new formula without much description on what it is.

>>10987677
its retarded in a kind of smart way

>>10986172
s(car1) = 0+vt11
s(car2) = 5000-v2t2
t1=t2 because they will meet at the same moment
0+vt1 = 5000-v2t2
0+80t = 5000 - 95t
80t+95t = 5000-0
175t = 5000s
t = 5000/175
t~=28.57
Now just do ((0+v1t) + (5000-v2t))/2 for averaged result.

>>10987684
Math should make sense instantaneously. It's the most logical anything in the world can be, yet many people fail to comprehend it. It's not like reading a book and having to interpret different points of view.

>>10985230
holy shit i answered yes in all of the questions

>>10987684
It does take some time to understand new concepts, but once you work out what its representing it becomes intuitive.
Simple example:
5+1=6 means nothing until you understand that 5 things and another thing are 6 things together, then basic addition becomes simple and logical.
This but with increasingly harder concepts.

>>10987794
What now Anon?

>>10986643
Power rules.
x^a * x^b = x^(a+b) =>x^2 * x^3 = x^5
x^a / x^b = x^(a-b) = >x^6/x^4 = x^2. x^2/x^-1 = x^3

>>10987796
I see, that's well said

>>10987796
People don't think of 5+1=6 as a number line or a graph?

>>10986204
>all these Year 1 things out of my reach
Where's Elementary Algebra and Intermediate Algebra?

>>10985230
every single thing here applies to me

>>10987806
suicide?

>>10988140
This or fixing your Problems

>>10985543
Took AP Physics in HS and I felt like I did shit in it even though I got a B

>>10988164
>tfw physics was already difficult enough

>>10985338
An hero

>20
>Diagnosed ADHD
>NEET for two years
>Semester Starts in 16 days
>started preparing 3 days ago
>still refreshing highschool knowledge
>never even touched university math
>psychiatrist said i scored above average in intelligence test

Im afraid everyone else is so much better prepaired and more talented than me ;__;

>>10988589
everyone is about as prepared as you are. i.e. not at all. if you put in work you will succeed

https://www.youtube.com/watch?v=SlCRfTmBSGs

>>10988589
Everybody get assrape by calculus, just focus
http://www.gutenberg.org/ebooks/33283

>>10988589
>Talent

Fuck, dude, you're learning CALCULUS. Engineers learn that shit and they're all retarded pseuds. Talent doesn't enter into it. Just put a fucking effort in.

>>10986217
Read the fucking post dummy, the cars are driving DIRECTLY towards one another.

>>10988819
that means they are driving parallel to each other. How can you be so fucking stupid? Now I'm retracting that benefice of deified grace I previously wished upon you. Burn in the heart of hell.

>>10985230
how long would it take for me to learn German?
I want to study engineering in Germany

>>10988823
DIRECT means DIRECT dude, not my fault you are two stupid to know the meaning of words.

>>10986217
“directly towards”

Two objects moving directly towards eachother will collide unless one or both change direction

Can someone explain this chart ? Does the book on the left cover all the material listed on the right ? Also what is the name of the first book ?

>>10985230
at 14-15 I learned calc 1-4, DEs, Linear Algebra, and introductory analysis.
this should be the standard. if you weren't here when you were 15 then you lack the resolve to be in math.
I'm 18 in uni now, I'll be graduating uni early because the college classes I took in HS will count towards my credit and major.
>>10987868
all of the algebra you know is elementary. most Uni expect you learned that in elementary school, where they teach you elementary concepts.

>>10988589
>ADHD
Is phsyciatry psuedoscience?

>graduate top 10 of my class in highschool
>get to college
>realize all the maths I learned thus far is a mismatched jumble of shit
>i barely feel prepared or stable enough in my fundamentals to continue
Im scared /sci/ what do I do? Should I just start at college algebra and work my way back up? I hate feeling so unsure in every equation I do now.

>>10989402
Start at whatever is below college algebra. You need to refine your foundation.

>be me
>Always be bad at math
>Following along with the problem solving is pretty easy
>Bad at replicating the problem solving formulas
>Im in Calculus 1
>tfw there's highschoolers smarter than me
>mfw

>>10989416
You just suck at algebra. Go back and relearn it. Calculus is meme tier.

>>10988939
'bout a year if you follow the AJATT method, but why the fuck would you wanna get your BS in Germany instead of in your home country (unless you live in, like, Zambia)?
If you're gonna study overseas, do it when you get your Master's degree or PhD (as if you ever will).

I got a 92% on my algebra 101 course. wew lad, wish I wasnt retarded

21 year old on his first semester of CS at a shitty third world university. I just failed my second Analytic Geometry test (which is only mildly harder than what I had back in high school) just because I'm slow as fuck at recalling procedures on how to solve stuff like "find the equation of a circumference that goes through 2 points and a straight line".
Is this an innate IQ issue that cannot be solved, or is it something that can be fixed by solving lots of problems every fucking day?

>>10989514
You just have to commit it to memory. It's both solving more problems and writing it down. Physically writing it is important

>>10986172
Kinematics is cool I guess.

>>10989417
>Calculus is meme tier.
that's because it's for meme things like engineering.
don't even bother with calculus, skipping it will hardly hurt you.

Didnt know this was a general. 6 months ago I was 24 yo NEET. Had dropped out of uni and kicked out of military. Fucked in the head and messing myself up even more with a shit ton of drugs and booze. Now I have a job (working on a farm but still) and sobered up. Everyone there is really friendly and nice too and doesnt know how big of a fuck up I am. Someone at work a couple months ago was talking to me and encouraged me to do something with my life. Started thinking about maybe going back to uni and switching to math. Decided to start taking some actuarial exams so I do something productive in case i ever do want to go back to uni. Just passed p this month and probably going to do fm in Dec. Were all gonna make it brahs.
https://youtube.com/watch?v=-aqkLKK8biM

>>10989417
Yeah I feel like I gotta go back and relearn the basics, just its just retaining things I dont do on a daily, weekly or even monthly basis. If I can tie it into every day life, I'm better at remembering it

>>10989791
Solve several dozens of practice problems off multiple sections in a Calculus or Algebra textbook. Check to see how long it takes to get through them and how much you can do without looking anything up or re-reading anything.
Makin it ain't just about passin entry exams. It's also about getting through several hours of classwork/homework from tons of different courses every fucking day for 4 years. Unless you're at a shitty liberal arts university where you get treated like a baby, the vast majority of your assignments will include a few tricky questions.
I know this might sound either obvious or demotivating, but I'm mostly saying this for the sake of putting your feet on the ground.

>>10987610
/g/ installs programs

>>10986213
based

>>10989428
well I dont live in Zambia, I live in Romania, which is pretty close I guess, stem is very weak in Romania we specialise more in human science and other meme degrees. I have a S in business management, and lm gonna kill myself if this is what l will do for the rest of my life

>>10990265
post more QTs before you die, ok?

>>10988939
too long. don’t bother unless you’re insanely motivated and have loads of free time.

>>10989416
do burgers seriously not learn calculus in highschool? we start learning it in 10th grade here in germany. also, how the fuck do people think calculus is hard? even my retarded ass passed with flying colors. it’s literally just mechanical grunt work.

>>10990271
only if you give me advice

>>10990286
Learn german
come to germany
do your studies
go back to romania or stay

Thats it

>>10990286
invest in tech and study in your free time. don't even fucking bother going back to school.

>>10989514
Analytic Geometry is nowhere near the threshold where practice can no longer compensate for a lack of IQ, so get to work, you lazy fuck.

>>10990292
>>10990287

>>10990298
No trannys!

>>10990298
I'd let him fuck me any day of the week.

>>10990298
what's with traps and guns

>>10990302
wtf man, you would let him fuck you?
are you a fag?

>>10985230

I'm 22 and have basically no math skills, due to my parents decisions. This really sucks. My parents moved me around the world, school to school probably 8 or 9 times, at times I'd go from one school, spend 6 moths there then go back to the previous school. I was a living in southeast Asia and being a minority I was often socially isolated and bullied, this made me retreat inwards even more.

Long story short I'm an adult now, my parents blame me for my inability to learn math even though they themselves agree that my development was stunted by their terrible life decisions. My dream of owning a small company is never going to come true. My only career choice menimenial labor. I don't have the time or the resources to learn the skills I want to make my dream come true, and if I were to take on student loans I'd genuinely break under pressure.

I'm not lazy and I do work hard but I feel like it's very naive to say the whole "pull yourself up by your bootstraps" in our current world this is basically impossible.

>Bre wtf does this have to do with this thread though?

Math is an essential skill, not something that you "might need" but something "you can't live without". I guess this is for all the people with motivation problems, if you don't want to be a looser before your life even begins learn math. Don't be me. Good luck.

>>10990313
traps aren't gay though.

>>10990325
if they fuck you in the ass is very gay, if you fuck them its not though

>>10990328
what if a woman fucks you in the ass?

>>10990329
you are a degenerate and will burn in hell

What is the best way to learn math conepts and really understand them instead of just memorizing and using tools to do the exercises? Say I want to start with really basic things such as linear equations with one unknown.

>>10990332
probably

>>10986172
Car1: 80x
Car2: 5000 - 95x

Intercept of two fucking linear for time.
80x = 5000 - 95x
x = 28.5 seconds

Re substitute time into any of those:
Approx 2286 m

>>10990334
memorize the process to solve such problems, then use your own brain instead of a tool.

any good quadratic forms intro? I'm reading the sensual quadratic by conway and wanting to go further.
My main interest are number theory and combinatorics

Can someone help me with the following question:

Construct a Taylor polynominal to approximate [eqn]\frac{1}{\sqrt{e}}[/eqn] with an error of less than 1/10.

Which x should I use to best to approximate the function in this question? Should I straight up use 1/sqrt(x) or maybe 1/sqrt(x+1)?

>>10989932
Thanks anon, I already scraped by 3 years of an engineering degree so I hope I can complete a math degree with another 3 or maybe 4 semesters. And I'm probably going to go to a state school where I live. If i do go back Im going to be treating it like a full time job unlike the last time I was there when I barely did anything. I always liked math but Ive never really taken upper level math specific course beyond differential equations, so maybe I don't know what I'm in for. My algebra and calculus is admittedly shaky at best though. I couldn't solve one problem on the exam because I was getting tripped up on the calculus and some of the problems I was using brute force with the multiple choice answers because I didn't trust my algebra. I probably could have solved them eventually, but not with a time constraint. Maybe it was just because Im rusty from not doing math in a long time, but I think I need to go back and relearn things that I was taught in school. And actually learn them this time, not just learn how to get the right answer. Im pretty determined this time around though and actually have goals now so things are looking up. Just kind of depressing relearning stuff most people learn in middle school or high school. Just have to keep working hard and getting better though.

>>10986172
5000/80=62.5
5000/95=52.63
62.5/52.63=1.187
1.187x+x=5000
x=2285.714
Is this right?

>>10988342
My teacher was shit at teaching. Knew the content just not how to deliver it.

>>10991003
Just realized i could have skipped the first 2 lines for 95/80=1.1875

>>10990560
Those wouldn't even work because when you plug x=e or x=e-1 you will have to approximate that too and you won't be able to control the error (or prove that you are controlling it)

Just use e^x and plug in x= -0.5 or some variation of that.

>>10990285
The school I attended stopped at precalc unless you were in the accelerated learning program which brought you up to calc

>>10985704
>become friends with weightlifter
>go to gym together
>cry because he can lift bigger weights than you
>give up
this is you. no one is born with it.

>>10989051
sounds to me like you're behind the curve. imagine not learning calc and lin alg when you were 13. lol.
what kind of shit school are you going to that accepts anyone who isn't starting in graduate level coursework?

>>10990318
it would literally take you a few weeks to go through the khan academy math curriculum beyond where you'd need it to be a business owner. stop crying and making excuses for yourself and start right the fuck now. you're just wasting your time on the internet, so go to the website NOW and don't come back until you've completed a few quick lessons.

>>10988375
based

>>10990276
I have time 2 years to be more exact

>>10991194
But how will your know you’re getting answers correct if there’s no one to check them?

>>10985230
Can i just show up to a high school in may and take ap exams? I want to test out of intro physics when i go back to school. Anyone do this?

>>10992103
I think khan academy has a submit button with immediate feedback and solutions

>>10992139
No, you need proof of your identity. Your exam for example won’t even be there.

>>10985230
How do I tell if my combinatorics research is an original idea?
I kinda just came up with a problem and solved it.
I tried googling it, but I can't find anyone who's stated the problem.
I'm still in undergrad, what resources do grad students use to find out if their idea is original?

>>10986172

Okay gamers, we need to use ratios.

80:95 can be simplified to 16:19.

16 + 19 = 35 (total distance in ratio)

CAR 1: (5000 / 35) x 16 = 2285.714m
CAR 2: (5000 / 35) x 19 = 2714.286m

Proof of correct distance and ratio:

2285.714m + 2714.286m = 5000m

I fucked it first time by dividing the ratios into each other and multiplying by the distance.

>>10992103
You won't be able to move to the next lesson unless you're getting at least most of the answers right. They check your answers for you.

I am trying to reteach myslef calculus. I find myself forgetting certain algebra techniques but dont know what they're called and cant easily search. Is there a glossary somewhere I can look at? Specifically how to factor and solve out exponents with variables inside, like 2 = x * x^2. I can get as far as 2= x(x+1) but forget how to go from here.

>>10992392
The law of exponents could probably just be googled.

>>10992400
I found some site that solves it and now I have it. Gotta set one half of the equation to zero, factor out the exponent, and set x so one of both coefficients are zero.

>>10991184
it's american, please don't make fun of my smooth brain country.
I had to learn it all on my own volition. :(

>>10991184
There’s no reason you can’t, but it’s pretty useless let’s be real.

>>10985230
My biggest failure is taking BS Secondary Education in Math when I don't want to be a teacher. Anyway, how do I improve my math fundies? I can easily grasp the concept of the topics, but I can't solve it due to me missing a lot of knowledge needed to solve the equation (ex. I have to actually simplify, but didn't do as I didn't know that was actually needed. Costed me a quiz for that mistake.).

Is KhanAcademy fine to hone my trash Math fundies?

>>10986204
Thanks dude

>>10985230
I’m originally came here because I want to not be a dumbass in hopes that something might rub off on me, but the more time I spend here the more I enjoy it

I'm trying to prove that [math] x^5 x^3 + 1 = 0 [/math] doesnt have any real solutions,
I understand how to solve it except for this part. If we take [math] x = \frac{p}{q} , p,q\in \mathbb{Q} [/math] why do we assume that p,q dont have common factors and are coprime integers with a gcd(p,q) = 1.

>>10992929
sorry i meant it doesnt have any rational solutions

>>10990495
thanks for nothing faggots

>>10987786
you’re wrong and probably not even done w/ calculus

>>10988980
>not my fault you are two stupid to know the meaning of words.
>two stupid to know the meaning of words
>two

this thread is a good place

>Highschool dropout
>Working a sales job and making decent money but don't enjoy it
>Dream is to go to university and get a degree in a smart field and get a good respectable job which I can be proud of

Is this a reasonable goal? Can I really make it?

>>10992194
we’ll try posting it here first u idiot

>>10985230
Would anyone be able to explain to me what the asterisk (*) in the line that says g(v) = g(q) - g(p) means?

>>10993019
Probably, you can probably just get a GED and then apply for colleges

>>10993033
But how much should I prepare in order to actually be able to get anywhere and how do I determine what to study?

>>10993035
Talk to college counselors.

>>10986179
3IQ, basics of point-set topology require nothing in your head.

assuming you know what is a set tho.

What does evaluating a given matrix by "inspection" mean? I can't figure out what they mean with "by inspection" means :/

>>10993017
What is your problem dude? You are just to arrogant two believe.

>>10991090
Ahh, thanks anon. I'm dumb haha.

>>10985230
Why is wolframalpha bugging out?

Also, what is the sum of the series [math]\sum_{n=1}^{\infty}-1^{n}[/math]? I mean when using the bullshit math where 1+1+1+1... and so on actually "equals" something.

Why is wolframalpha bugging out?

Also, what is the sum of the series [math] \sum_{n=1}^{\infty}-1^{n} [/math]? I mean when using the bullshit math where 1+1+1+1... and so on actually "equals" something.

>>10992929
>why do we assume that p,q dont have common factors and are coprime integers with a gcd(p,q) = 1.
Because every rational number can always, always, be put on that form.
You cam always simplify, so taking the number already simplified makes your life easier. And because it makes easier to derive a contradiction in this case

Any thoughts on this book ? Also is introductory point-set topology doable at precalculus level with some complementary research ?

>>10994174
Look at the sci wiki and university course descriptions for prerequisites
also
those books are generally good for the price

Does anyone recommend Feller's two volumes on Probability?

>>10994306
Yeah I own quite a few books from Dover, the texts are great and the books dirt cheap.

>>10990286
There are lots of engineering degrees taught in english in Germany. Go do one of those.

>>10986648
>>10986827
not true, you can use l'hopitals rule to work out the value at x=0 to find out its not an exception

>>10996088
you're wrong. x^2/x is undefined at 0, period. the limit exists and all that, but a priori it's still undefined.

>>10996117
i take mine back, i thought the questioner meant something different

For more seasoned self-studiers, how do you test yourselves? Do you even bother?

Currently working through Axler's Precalc text and it's all going swell but I just move on section to section, chapter to chapter after I complete the exercises without looking back. Technically it's all review but I don't know if that's the best way to retain information. Is there a website with problem sets in precalc with a similar amount of rigor to Axler's exercises just to check my retention periodically?

At least once(if) I hit Calculus I'll be able to use MIT's course materials as a test

>>10985230
I barely passed ordinary Diff eq with a hardass professor over the summer with a B. Should I consider a math minor as an EE major (inb4 hahahahaha engineers cant do math). Im also interested in the Putnam exam so what materials should I study if I plan to take it?

>>10997348
>how do you test yourselves?
By taking a practice exam from a repository of college course test banks?

>>10986485
7root((3/4)^5)

check parenthesis anon

I'm having trouble with permutations. Let's say we have four letters: A, B, C and D. How many permutations are there for a sequence with the length n > 4 that includes at least one of each letter?

Do you think S&Z is a good precalc book? I've already tried it, and honestly I really like the way they explain concepts but the exercises are too easy so I forget everything.

fucking 9x redundant notation
fucking 4x redundant naming of concepts
fucking faggots seemingly trying to trip up the reader with their idiosyncratic notation and variable names/usage
fucking tiny italic fonts
fucking ambiguity
fucking greek shit
fucking maths

>>10999204
If theres only 4 letters how can n be > 4?

>>10997401
>so what materials should I study if I plan to take it?
Study older Putnam tests

>>11000344
You can repeat.
>>10999204
Fun problem.
So we can count it constructively by summing up all n sized permutations with spread (a,b,c,d) of each symbol with a+b+c+d=n and all a,b,c,d>0.
So there's n!/(a!b!c!d!) factorial permutations with a As, b Bs, c Cs and d Ds.
As for how many terms to sum, consider n stars and 3 bars. What gives n + 2 choose 2.

Dunno if there's a simpler expression

>>11000376
>What gives n + 2 choose 2.
Oops, forgot to remove terms with a zero term. Sorry anon.

>>11000376
>>11000381
I'm retarded, sorry.
So given a permutation of size n we can force it to have at least one of each letters. Pick 4 points and put one of each letter on those spots.
There's (n, 4) ways of making the choice and 4! ways of placing the elements.
So there are (n, 4)*4! possibilities.
Now we just need to count how many sequences of size (n-4) with 4 symbols exists. But that's just 4^(n-4).
So (n, 4)*4!*4^(n-4) should be the answer

>>10986217
man you're fucking retarded I hope you die a painful horrible death cuz you deserve no better

>>10988790
>all retarded pseuds
>all
Hello there God.

Are you always required to create a fraction out of these problems? They textbook wants you to multiply top and "bottom (1)" by the conjugate and come up with 1/6. I was thinking that you would just simplify the problem by taking the square root of 9x^2 to just 3x ending up with,

3x + √(x) - 3x,

which would just leave you with √(x) and thus the limit would go to infinity, but this is wrong.

>>11000743
[math]\sqrt{a+b} \neq \sqrr{a}+\sqrt{b}[/math]
You do understand that, right?

>>11000743
[math]\sqrt{a+b} \neq \sqrt{a}+\sqrt{b}[/math]

>>11000756
ahh yes, it's only multiplication under the radicand that can be simplified. blessings to you

Question:
>>10986172

Calculation:

For the sake of simplicity both cars are driving to the north. Therefore car2's velocity is negative.

Car1: m = 80 m/s × s + 0 m
Car2: m = -95 m/s × s + 5.000 m


m = m

-95 × s + 5.000 = 80 × s // +(95 × s)
5.000 = 175 × s // ÷175
28,571428571 = s

Car1: m = 80 ×28,571428571 = 2.285,7142857
5.000 - 2.285,7142857 = 2.714,2857142

Answer:
Car1 will meet car2 after it drove ~2.285,7 m north.
Car2 will meet car1 after it drove ~2.714,3 m south.

How would you go about making a formula for these constraints? I don't really know where to start. I figure plugging in (x-2) in the numerator will do the f(2) = 0, and a basic understanding that the formula might have a 1/x sort of thing, but what is a good strategy to fill in the rest of the stuff?

>>11001147
Nevermind, I sort of found a guide. I guess the idea is to just do it piece by piece with each constraint.

>>10993023
What benefit would posting it on an anonymous image board be?
If it is original anybody could take credit for it.

I’m a brain let trying to make my way through a discrete math course for compsci. I’m already blustered by the content. It’s discrete math 2, so probability is coming up, we just did counting and today we learned about pigeon hole principle. It’s very hard to understand. Where do I go to learn this stuff? The only resource he gives is a textbook with a few exercises without explanations.

>>11001207
It was this in particular that threw me off.

>>11001225
Missed a part

Having trouble with a differential equation
y' +2(x^2)y = x^2

I get the correct answer when using separation of variables but when I try to do integrating factor I get a different answer than the correct one.

Separation of variable = (C1/2)e^(-(2x^3)/3) + (1/2)

Integrating factor = (1/2)e^((2/3)x^3)

Can't for the life of me figure out what I am doing wrong. They should always be the same right?

How do I prove something with well-ordering principle?

I have to prove: for all natural n, [math]n\ \geq\ 2[/math] it will have a prime factor

1. Define set of counterexamples:
[math]
C = \{ n\ \epsilon\ \mathbb{N}\ |\ n \geq 2 ,\ has\ no\ prime\ factor\}
[/math]
2. Assume set is nonempty.
3. By Well-Ordering, there must be a least element.
4. If [math]C_{0}[/math], exists. It must have at least 2 factors, 1 * a, a * b.
5....
idk what to do.

Guys how do I do proofs? I know the techniques but when I'm given an exercise how will I know if it's right or wrong?

>>11001987
By WOP there exists a least element in C.
Set k to be a fixed smallest integer with the property "has no prime factor". Then k-1 has a prime factor since we defined k to be the smallest integer that has no prime factor. Show from k-1 that k does in fact have a prime factor. Contradiction, so assumption is false.
Something along those lines should work.

>>11002230
But how do you show that k-1 does in fact have a prime factor?
k - 1 is greater than 2 and that's all I know?

>be 27, almost 28.
>Completed biology undergrad in a shitty college, even by 3rd world standards.
>Shitty country has virtually 0 biology jobs. In the rare event
there IS a job to be done they will want it for free and some retard will give it it them for free.
>No money for overpriced masters degree. Have to help take care of family so can't just fuck away to another country with "free shit" like Germany.
>Enrolled in uni again for software engineering. yet another shitty college (at least it is dirt cheap).
>Still love the science but I feel like I am at a dead end.
>Still unemployed.

Should I just give up?

>>10986204
>he wants this schedule but actually needs sources for even second year books

Man just fucking open up rudin, axle, munkres, and herstein and see if you want to do any of your 4th year classes you LARPing meme.

>>11002267
What country are you in?

>>10997348
Try using a spaced repetition algorithm for material you've already learned. Anki flashcards do this automatically, for example, so you can throw some concepts or exam problems into Anki and do an hour of review per day.

>>11002278
Colombia.

>>11002625
Damn, stay strong anon I hope you make it.

>>10985230
Why is math SO boring and dull?

>>11002791
I think it’s exciting sometimes. It’s not when learning something that seems like a pump and dump kind of information though.

How did you guys get back into math? I have a GRE to worry about soon and I haven't done Math in quite a long time.

>>11002791
it's not like that for smart people. every human gets a bit of a kick when they solve a problem, but smart people are able to get bigger kicks from harder problems, and so are psychologically capable of studying long hours per day in uni and maybe having an academic career.

I'm so overwhelmed by the amount of content I need to learn (Calc 2 and physics) and I'm falling behind because I'm just scared of tackling them. Bros... how do I make the first step...

Does ML generated rare pepe anon still post?

>>11003044
u dont giv up

>>10989691
I have that same board in my dorm lmao

i've spent all my days at school doing nothing that has anything to do with numbers. is it possible to learn things now that i am already in college or should i just do the same as i was in school(cheating)?

>>11003044
Just sit down and start doing it. It will only get harder if you let yourself get farther behind so there really is no better time than right now. If its concepts you dont understand I would try watching videos with good explanations, but if its the math part that you are having trouble with then you just have to do a lot of practice problems.

>>10986172
>directly towards one another
they don't pass, they crash. trick question

>>11002068
Usually you have a professor to look them up for big errors (or friends to discuss the proofs with). What makes me wonder how those American classes with 100+ students could possibly work.
Re-read all the relevant definitions and go slowly through your proof checking why each step follows and where every hypothesis is used.
As for how one learns to do proofs, read lots of proofs and do proof exercises from the book. If the book skips a step or disregards something as obvious/simple, you must provide the proof. When I was getting started I remember asking a professor something like that and she said "write the hypothesis on the top of the sheet and the conclusion at the end. Then try connecting them". It worked for me.

Guys I want to reach the level in pic related
What math is actually written there and from where to start?

>>11004189
A quick glance make it looks like stats (by what's written I guess it's from a solid mechanics/strength of materials book?).
Anyway, it uses lots of Calculus, Analysis, Linear Algebra, Probability theory, Statistics. stats, but dunno. That's from the top of my head.
If it really is strength of materials you will need some ODEs and PDEs (if you want to do elasticity, fractures, etc) and tensor calculus (most solid mechanics is written in tensor language). Basic (and some not so basic) physics also goes without saying.

>>11004189
Things like this are so cool. Makes me really want to learn math despite being slow at it.

>>10988164
Probably did shit anyway cuz HS physics don't matter

>>10989691
For the middle part how did you determine to use 80m/s instead of 95?

I just did my first Physics test (I am doing ME). And got a 0.
I studied as much as I could, did all exercises, paid attention to the classes, etc.
I got like halfway into the questions and just had no idea what to do anymore.
This never happened to me before. Am I just not made for this?

>>11003137
Cheating isn't worth it if you actually want to learn, and chances are that you'll need to learn to get to where you want to go. Since you're used to cheating, the process of studying math with probably start off feeling really hard, but just take breaks and keep your ultimate goal in mind. Don't give up.

>>11004257
Don't forget measure theory

>>10987865
Wow I feel dumb. I'm in Calc 3 and even sometimes now I forgot for a split second what 1-2 is or 2-3, honestly anything that equals negative one. And now I'll just force myself to thing of the number line. Thanks anon lmao

>>11005627
Failure is a part of the process. Some people face it so late in the game that they never learned how to deal with it, and they just give up. It's not "good" to fail a test, but it's better that you experienced failure early in your degree so that you learn how to deal with it. Before Real Analysis 2 in undergrad, I never went to office hours or studied with other people because I always wanted to ace my classes alone, so when I almost failed the class, I had no support network for dealing with my confusion with the material. Seriously, go talk to people, try to explain your solutions, and ask as many questions as you can without coming off as annoying. I learned that there's a lot more to learning than just studying.

losing my patience with calculus. it's just one rule after another, my memory is overflowing, i'll never pass a test.

>>11005951
What rules are you struggling with?
Also don't give up, everyone feels like that because Calculus is often taught in a stupid way

Can anyone recommend a good book on just multivariable calculus? I'm studying for the math subject GRE and I feel really weak on that subject. Doesn't help that I transferred into my math program after having taken Calc II and my program teaches calculus in a weird ordering.

>>11005977
Lang's Multivariate Calculus
Courant and John's Differential and Integral calculus vol. 2
Apostol's Calculus volume 2
Susan Colley's Vector Calculus
If you speak Portuguese (or Spanish, what is close enough), Guidorizzi's Um Curso de Cálculo vols 2 and 3 are good too .
Hubbard & Hubbard's Vector Calculus, Linear Algebra and Differential Forms is pretty good (despite introducing Differential Forms it also introduces the usual vector calculus stuff)
They all should have everything you need and them some.
IMHO, Lang is the easiest, followed by Colley and Guidorizzi. Hubbard and Apostol should be roughly equivalent, while Courant is a bit tougher

>>11000780
Good answer. I was trying to understand it from this perspective, but didn't get to the point of making the one the graphs negative sloping by putting a minus sign in front of the gradient.

Also good >>10992215, had no idea how to think about it using ratios.

Here's a stupid brainlet algebra 1 question for you guys.

If I have a transformed function f(bx - c), I'd have to shift it's graph c units to the left/right and stretch/shrink it by a factor of 1/b to get the correct graph. I know that, but why wouldn't I start with the horizontal stretch/shrink first? I just want to understand it intuitively and not just compartmentalize it as a rule like I did as a kid.

>>11006254
Pick a function, a stretch factor and a displacement and plot the result of doing it in the two ways. Geogebra is dead simple to use and works well for this sort of things

>>10989009
FYI that's a meme list.

>>11006279
Or just note that x/b - c = (x-bc)/b and you displaced it by bc instead of displacing ot by c

>>11006293
Oops, meant for >>11006271

I am a brainlet with a BA in literature whose math knowledge stops about halfway through high school, but I appreciate you guys.

>>11006327
thanks i would like to lick your nose

>>10985230
i want to learn about analytic and algebraic number theory so i have an idea of if i think i have any shot at doing a math phd. probably not because i'm not very smart. also i have to learn more complex analysis first because i only know the basics.

>>11007005
Basic analytic number theory doesn't use too much complex analysis (you can go through Apostol or Chandrasekharan with the stuff you get on a first course in complex analysis), so it might be worth a shot.

Could anybody explain these two problems? I’ve been stuck on them for awhile.

>>11007072
The second question is too ambiguous.
>The water is 6.86cm deep in the cup.
That could either mean the height of the water in the cup is 6.86cm. Or it could also mean the distance between the top surface of the water and the top of the cup is 6.86cm. Leave that question blank. Whoever wrote it doesn't merit an answer.

>>11007097
I was actually thinking this myself. My entire assignment is full of vague explanations where it is arguable that there isn’t enough information given.

Hey, do you people in this thread believe it is possible for an 18 year old community college student who's majoring in mathematics with pretty poor skills in the subject to be come a mathematician? I have a C in my math class btw.

>>11007121
I think its 3.9355

>>11007072
>ask your teacher option
The fuck? Never had this before. What’s the chapter name and concept though?

>>11007491
The Laws of Motion and Circular Motion

>>11007451
Why? Explain please.

>>11007491
Also I have tried the ask your teacher option. He doesn’t reply.

>>11007072
How would the acceleration in the j direction be negative?

>>11007072
Use the formula for centripetal acceleration to find your acceleration's magnitude. Then use trig to find the directions.

Can you get a job if you learn math? I am the brainlet described in the OP greentext. I'm really socially impaired but if I get good enough at math can my skills just speak for themself and get me hired?

>>10987865
No they dont because basic number theory and algebraic geometry are nowhere to be found in the public education curriculum, they have no idea what a set or field is. Its actually beyond retarded because you constant hear "you know some people are just visual learners" to try and mitigate idiots not being able to perform basic academics.

>>10990285
In many school boards calc is an elective or part of the AP(or equivalent) classes. EG, in my Canadian HS you only were exposed to calculus starting in grade 11 if you took the more advanced math class. Despite what some anons on here like to say European HS in non shithole countries is quantitatively superior to NA excepting some private schools.

>>10990328
It upsets me that some renaissance painters spent a few centuries developing their art and then in the 21st century it gets used for this garbage.

>>10993035
Depends on how smart you are. Every uni offers remedial classes in every subject for students who didnt take the required classes in HS but want to major in something that does. If you are capable of learning everything necessary from those classes in 1 or 2 semesters then you are golden.

Could someone help with this question?

A cup is designed out of the following linear function rotated about the y-axis with the start and end points specified at (10,0) and (20,20) respectively.
Water flows into the cup at 3cm^3/min.
Find the rate of change of height when the depth of the cup is such that the radius is 17 cm.

>>11008189
Figure out the equation for that line. Remember to solve solve it explicitly for x since you're rotating about y axis. This will be the radius of our container for a given y.

Now we set up an integral from 0 to h. Our integral will be the solid generated by our radius function when rotated about the y axis. Evaluating this integral will give use a function for volume with respect you height.

Now implicitly differentiate the volume function and solve for dh/dt. Additionally, solve your radius function when the radius equals 17cm. You now have all the variables needed to plug into your dh/dt equation.

I worked it pretty quickly and got approx .0033cm/min

i give up

>>11007664
https://m.youtube.com/watch?v=TIBcntHCxjQ
This video explains it good I think. Something to do with the forces cancelling out and giving you w=sqrt(g/r).
r has to be .702m-.0686m because thats the only way you can get a radius from that question. And g is 9.81. Not sure if its right. I honestly didnt even watch the video. Just found the formula.

Realistically how much will i have to remember from all my math classes? I really hope it's not everything because my memory sucks

>>11001207
>>11001225
>>11001232
I took discrete math a long time ago but this video helped me figure out the basics:
https://www.youtube.com/watch?v=4Dz4vNUxnZM
its by MIT OpenCourseWare, and the prof in the video can actually speak english which is nice
Ill work on a step by step breakdown on your images for another post here in a bit

I've forgotten trig.

>>11001207
>>11001225
>>11001232
this is another way of proving there are infinite primes, still working on a breakdown of the example proof you posted

>>11010731
forgot link fuck me
http://web.math.ucsb.edu/~helena/teaching/math8/handouts/primes.pdf

Good resource for linear algebra? My class just got to vector spaces, subsets, and subspaces and I'm a little lost...

>>11001232
>>11010731
>>11010745
This is the proof I learned in discrete as well.

>>11011018
What textbook are you using and what's wrong with using that?

>>11010647
The most important thing in math classes is that you understand the proofs. Even if you forget the proofs later on, being able to understand them is the most important thing.

>>11001207
What's so hard to understand about pigeon hole principle?

If I have more holes than pigeons, then there are empty holes.

If I have more pigeons then holes, then there are holes with more than one pigeon.

If I have equally many pigeons and holes, the I MIGHT have no empty holes.

>>11011094
But why is it that there might be no empty holes?

What does the bold x function even mean?
Do I have to solve for x or something?

>>11011926
I don't even speak german, and I can't tell that x stands for a differentiable curve which satisfies the condition below. You input a real number t and x(t) is the coordinates of the curve at that parameter.

>>11011099
The fact that if I have more pigeons then holes, then there are holes with more than one pigeon, doesn't say anything about empty holes. There might be some, there might be none.

>>11011934
Oh thanks, so it's like a mystery funktion and the two composite funktions give me some hints about it?

>>11011939
It's not a mystery function... The questions essentially asks you to prove that for ANY differentiable function x(t) satisfying these conditions, x'(0) will always be the same, which you want to calculate.

>>11001444
I found the same answer using both methods:

[eqn]y^\prime + 2x^2y(x) = x^2 \Rightarrow e^{\frac{2x^3}{3}}y(x)^\prime + e^{\frac{2x^3}{3}}2x^2y(x) = e^{\frac{2x^3}{3}}x^2[/eqn]
[eqn]\left[y(x)e^{\frac{2x^3}{3}}\right]^\prime = \left[\frac{1}{2}e^{\frac{2x^3}{3}}\right]^\prime \Rightarrow y(x) = e^{\frac{-2x^3}{3}}\left(\frac{1}{2}e^{\frac{2x^3}{3}} + C\right)\Rightarrow y(x) = Ce^{\frac{-2x^3}{3}} + \frac{1}{2}.[/eqn]

>>11007072
Find the radius R of the circle (you know the circumference). Calculate the angular velocity [math]\omega[/math] (you know the angle you traverse and how long it takes). Calculate the centripetal acceleration, take into account it always point radially inwards and decompose the vector with the angle given. You might want to draw that last part because as >>11007906
has stated, it makes little sense for both components to be negative. I'll help you later if you can't find it.

/mlg/ official discord server
>7gVwUJ

>>11002259
Strong induction. Either k is prime (and thus has a prime factor) or it is not. If it's not then k = ab where a and b have a prime factor by assumption.

Is it possible for diff eq to be fun? So far it's been sort of thrown in with other material in my courses, slowly expanding methods on how to solve them. It just feels like a complete mess of a subject, like if we were not to study triangles using trigonometry, but instead started classifying different types (Isosceles, equilateral, right, etc.) and have different solution methods for each.

>>10985230
>be always bad at math
>dont go beyond geometry in complexity in hs
>have to take pre-calc in college because hyper brainlet in hs
>it all just fucking clicks because my instructor is god tier and it makes sense to me
>mfw we're all gonna make it

>>10989009
I feel like that's more math than 12 people could possibly be expected to pull out of their asses

>>11007434
That was me 5 years ago but instead of being a mathematician I did mathematical physics which is the same thing but harder

Currently retaking the courses I got C's in so they don't think I'm some retarded /sci/poster with DKE

Lads, i fucked up long ago but now as the new semester has started for others, and im sitting here in my room looking for jobs and doing some light studying to prevent my brain from collapsing on itself, only now do i understand the severity of my situation.
>2017 graduated from highschool with top marks as a autistic low companionship retard who only went to school and went straight back home to study for hours on end and wasting sleep hours on vidya.
>Got a job at walmart for the summer, was shit work, but money is good.
>Didnt hang out with friends alot during summer, maybe like 4 times tops.
>Enrolled in pre-engg at local uni with 2 of them.
Thus the chaos ensued
>freedom and more contact with others felt great, i was understanding and doing good during lessons and tutorial classes
>quizzes were easy, tests were also easy but sometimes got less than 80% on them, but it was fine
>then came midterms, hard 60% on almost all of them, but then again this was the norm for the majority of the class.

>>11012545
>Brought my marks back up with weekly assignments and good quiz marks
>late nights with the gang doing compsci assignments, sometimes we snuck in alcohol into the lab and sipped and wrote shit code
> smoked weed once, didnt really do much, just listing as part of the timeline
>Quit work because it was cutting into study time and was hassle to get from one side of the city to the other
>Finals time
>barely pass all of my classes except Compsci, which i actually failed due to drawing a blank during the exam.
>I actually fucking cried after my static engineering final knowing how badly i fucked up
2nd semester starts
>Know that i can still make the transfer quota if i hunker down and do good this semesters classes and retake compsci in the summer
>1 week in i get an email of being on academic probation due to shit gpa
> confidence drops, cant focus in classes
>squeeze by assignments and quizzes, get fucked on the tests, exams and midterms.
> Dont do the finals cause i drop out of all the classes to prevent required withdrawal

When I do math problems, I give up almost immediately within the first 3 minutes and get external help. Every time this happens, I start to doubt my abilities and my self-esteem goes down . How do you guys become more 'patient'?

>>11012572
>switch my program to compsci for the fall semester cause i can no longer take engg at this uni
>spend entire summer looking for job, but remain unemployed, studying up compsci in the meantime to make sure i dont fail again
2018 fall
>take compsci, math 1565, and microecon
>pass compsci and math, fail econ cause landwhale proff wasnt in class for most of the semester cause she broke her foot waddling on uneven pavement, also cause im a fucking bad student
BAM academic probation with great concern, somehow still in uni, given a 2nd chance
Spring semester
>take math 2560, compsci logic(didnt involve computers), and micro econ again
>passed all my classes, but good enough
>gpa still too low
>required to withdraw
>cant reapply till 2020 fall
>got a job in a factory, processing chicken with immigrants and niggers
>quit to go on vacation with family
> comeback a month ago and cant find job
Im in hell and i cant stand to think about the future. I still want to be involved in academics, but im still not solidified in what i want to do even after 20 years of my having passed by.
I thought i was good with numbers, but then engg and physics fucked my shit up in uni.
Thought compsci would be easy since i good with computahs, turns out im retarded and cant remember c++ enough to write out programs with pen and paper
I just want something to happen, job or death, i cant stand my own shame and the shame thats induced by parental berating.
Im trying so hard, im still applying myself in light learning, im in hell.

>>11012042
I can’t. It makes no sense. I did 207*4 to find 828 then divide that by 2pi to find the radius which is 131.78. I took that and multiplied it by (pi/2) then divided that by 32s to get... 6.46875. So r*w equals the average speed? Plugging that into what now? -rw^2cos(wt) -rw^2sin(wt) ? Also, considering that angle B is in the fourth quadrant, wouldn’t it be 325 degrees? Is the answer -3.710i+5.299j?

Bois, any book list to dummy tier till Gauss?
Already doing khan academy, on my way to finish all content.

>>11012669
There's a saying that goes like this: A smart math major could teach Fourier some nee tricks, but not even the best math PhD could hope to teach Archimedes how to be a better mathematician.

>>11012698
new tricks*

>>11012698
Tank you for your wisdown noble man. I'll find my path.

Brainlet here
How is taking out a constant from an integral the same as keep the constant within the integral ? I end up with different arbitrary constants.
See pic related

>>11012727
One is negative the other is positive.
I should have multiplied by another integral than 1 to explain my idea

>>11012727
>arbitrary constants.
This means that C is anything. So -C,+C, K, W it could be anything. It's an arbitrary constant.

>>11012756
Yeah just figured it out in my head.
Thank you.

>>11012626
I think you're correct up to the angular speed. [math]C_{circle} = 4 * 207\ m = 828\ m \rightarrow R = 131.8\ m[/math]. The angular frequency is [math]\omega = \frac{(\frac{\pi\ rad}{2})}{32.0\ s} = 0.05\ \frac{rad}{s}[/math]. The centripetal acceleration is [math]a = \omega^2 R = (0.05\ \frac{rad}{s})^2(131\ m) = 0.33\ \frac{m}{s^2}[/math]. Look at the vector a in the picture, it's in the second quadrant with angle of 145 degrees. Decomposing a then gives [math]a_x = a \cdot cos(145 \circ) = -0.27\ \frac{m}{s^2} , a_y = a \cdot sin(145 \circ) = 0.19\ \frac{m}{s^2}[/math]. I think, if anything's wrong I'll take a look at it.

Guys any books that teach you mathematical tricks and problem solving up to calculus level?
Like the problems they use in math olympics
I don't want to learn new concepts, I want to learn how to think in problems

Any tips on how to study math effectively, I'm currently struggling with discrete mathematics in college

>>11012927
I've heard this book is good, haven't read it myself though.
https://math.hawaii.edu/home/pdf/putnam/PolyaHowToSolveIt.pdf

>>11012581
Take practice exams or even just groups of random questions under exam conditions. Dont look at the solution after each question because then you wont really try to solve it, you will just give up and look at the answer. Do the whole exam and then go back and look at the ones you got wrong and make sure you understand it.

Is it reasonable to assume that addition is not compatible with complex numbers? Every time the rectangular form is involved, you end up having to do weird, convoluted stuff like renormalization, computing magnitudes, or having to remind your inverse tangent which quadrant it's in.
In the spirit of Pannenkoek, is it even possible to do complex computations using no addition?

>>11008929
Is don't think this is right, what error did I make?

>>11013237
Thanks, just what I was looking for

>>11013493
confusedanimegirl.jpg
Retangular form is a+ib qnd addition is (a+ib)+(c+id) = (a+c)+i(d+c)
It gets complicated in polar form (and in phasor form), but multiplication becomes much simpler then.

>>11013678
That's my point, imo having to switch between the two indicates something is wrong. Especially since the process of switching, with squares, roots, and tangents, requires human intervention.
As an aside, and as a challenge, I was wondering: is it possible to express "addition" purely as multiplication between polar forms? Perhaps using an order of magnitude larger polar form as an intermediate?

How the fuck am I supposed to remember how to do all of this when I learn so much every single day? It's like the very next day I forget what I did previously and it just builds up until the end.

I don't understand Trig proofs at all, I've spent the last 3 hours failing to prove different trig identities. Am I too fucking stupid to pass actual calculus classes? I have been able to do all the precalc work that didn't involve Trig identity proofs, should I just drop everything and switch to accounting or some shit?

>>11013856
>tfw feel the same and there's still much more further and complex math ahead
I want to believe us brainlets can make it through though.

I keep doing really stupid shit and i need answers as to what's causing it. So clearly /mlg/ is the best place to go.

I've been studying for a math placement test in university (I changed my major from humanities) and while going over some old stuff things have been going really well. I remember most of the old stuff and those things which I don't get immediately I can usually work out within a few minutes of investigation and I rarely have to refer to a second source to see how to do something.

HOWEVER. A glaring fault in my mathematics has become apparent: that I keep making stupid little mistakes.

For example: doing polynomial long division between 5x^2+24x-34 and x+6. I went all the way down the chain like so:

x+6/ 5x^2+24x-34
5x^2/x
quotient 1 = 5x
5x * (x+6)
5x^2+24x-34 - (5x^2 + 30x)
= -6x -34
-6x/x = -6
quotient 2 = -6

but then I fuck up.

I say that -6 * (x + 6) somehow equates to -6x + 6. I completely forgot that the other 6 was there or something. I don't know. It's so weird and I do this shit all the time. Am I just retarded? Like, I know how to do all these equations all the way up to the brief calculus class I took as an econ pre-req but I keep being dyslexic like never before. Is it because I'm really rusty? I haven't done serious math in about a year, since that brief calc class so it's possible. I don't know. Please help.

Also sorry for the massive wall of shit.

>>11013515
>>11008929
Never mind I found my brainlet error, I have 0.0033 now.

>>11013812
Why wrong? You can multiplicate by normal algebra, and it's easy. But the geometrical interpretation is easier for the polar form.
You can probably find some mapping depending on w and that sends z to z+w directly, but dunno of it's simpler.

>>11014089
Why not use synthetic division when diving by a degree one polynomial?

>>11014266
>You can multiplicate by normal algebra, and it's easy.
Does division work though?
>You can probably find some mapping depending on w and that sends z to z+w directly
What do you mean by z and w?

>>11015482
Hey! You just reminded me that existed... again, t's been a while. Firstly, I forgot that existed. Secondly, the exercise was explicitly about polynomial long division, not synthetic division, so I was obliged to use that.

>>11007072
The second question -is- a bit ambiguous, without any information on the profile of the cup, let's assume the water rises up 6.86 cm from the bottom of the platform. The height from the top of the liquid, in this case, is [math]R_{top} = 70.2\ cm - 6.86\ cm = 63.34\ cm = 0.6334\ m[/math]. Equating the neccesary centripetal force and the force of gravity then [math]F_c = F_G \Rightarrow \frac{mv^2}{R} = mg \Rightarrow \omega = \sqrt{\frac{g}{r}}[/math] where I used the relation [math]v = \omega \cdot R[/math]. The minimum angular frequency is then [math]\omega = \sqrt{\frac{9.81\ \frac{m}{s^2}}{0.6334\ m}} = 3.94\ s^{-1}[/math].

>>10985230
requesting measure theory books, with pure measure theory, halmos is dated! no dynkyn systems, etc! if there's probability even better, but optional!

>>11012926
Wow. You were right. So how about part c? So far I am plugging in velocity formula but no luck.

>>11015615
>division
If z, w are complex numbers division is z/w = zw*/(ww*) where * is complex conjugation, so if z = x+iy and w = a+ib z/w = [(xa+yb)-i(ya+xb)]/[a^2+b^2]
Not so convenient, but easily doable

>>11016651
Axler?

>>11016651
>halmos is dated
why?
>>11017091
nice

What would you say is an average completion time (in hours) for subjects such Algebra 1, 2, and geometry on khan academy?

>>11017869
~160 hours probably

>>11018469
Each or total? I should have specified that orignially

>>11018485
Total

new when

hi retarded here couldn't pay attention at school I need to learn the math of 11-12 grade and I want to learn them fast