/sci/ - Science & Math

How do I begin to do proofs in Linear Algebra? How do I even begin to tackle these proofs? What are the format/notation conventions when writing a proof? help me /sci

For example:
1. Prove that if a matrix B can be obtained from a matrix A by a single row operation, then A can be obtained from B by a single row operation.

2. Prove that a matrix that contains only zeros in one of its columns can not be row equivalent to a matrix that contains at least one non-zero entry in the same column

3. If (A|b) is in reduced row echelon form, prove that A is also in reduced row echelon form.

Is there a stats textbook equivalent to Stewart for calculus? My prof uses his own textbook, in fact the entire department uses it. Needless to say, its a cash grab with little to no information at all. Any textbook recommendations?

If an irrational number like √2 or √7 can be raised to the power 2 to become rational, can something similar be said for something like e or π?
What I'm asking is: is it possible to raise π/e/γ to a rational, irrational or imaginary power and calculate a rational answer? Is this difficult to prove/disprove?

If f(x) is continuous and differentiable on the interval (a,b), and f ''(x) >0 for all x in (a,b), is it true that f '(x) >= f(x)/(x-a)?

In other words, is the slope of the tangent line at some point x always greater than or equal to the average rate of change from a to x if the function is concave up?

This is not homework. I made this assumption, in order to verify an inequality for elliptic functions. I was wandering if this is actually true. I thought I should probably prove it, but didn't get too far. Then again, I'm not 100% sure this assumption is actually true for all cases. Any insight?

Could someone help with Fibonacci numbers and the golden mean? I was reading up on some sites I found on Google but I'm still confused. This site (http://www.maths.surrey.ac.uk/hosted-sites/R.Knott/Fibonacci/phi.html#simpledef)) says that Phi^2=Phi+1. What were the steps they took to get to Phi+1?

Why is pre-calculus so much more difficult than regular calculus? I was near failing during Polar equations, conic functions, and partial decomposition but I just got a high 90 on the derivatives test we just had.

20 year old alcoholic here. Cannot get anything to drink and I am considering drinking mouthwash. I can probably jerry-rig a distiller out of hose and a pressure cooker. Lysterine has
* Chlorhexidine gluconate
* Ethanol (ethyl alcohol)
* Hydrogen peroxide
* Methyl salicylate
But I dont have the concentrations and I don't know how lethal it is
Any chemists with advice?

OK /sci/, Let's Make a very large thread and hope it gets stickied. I want moot to know, that we want a damn philosophy board! It would take care of the religion and overall philosophical threads with nowhere else to go. moot had the right idea with /soc/, let's do it again. Meanwhile, discuss what you think was the most important single discovery in science thus far. GO

>>2194115
Oh nice he has a lot of books, thank you!

my favorite.

It has occurred to me that we don't have proper notations for expressing bases.

Now, you might say that "you can put the number under subscript", but let's say you're dealing with base ten. And you put "10". What does 10 even mean to someone who doesn't already know it's base ten? It's equivocal.

Under base eight, 10 = eight. Under base 2, 10 = two. And if you go above ten, it is still as, if not even more, confusing.

Simply put, our bases cannot be expressed in double digits, other than the arbitrary decision that bases be expressed in base 10.

>>1973823

Fucking this. I'm pretty sure this is the only reason I got into a good U, from a mediocre community college with bad-mediocre grades (I didn't give a shit until recently), I made it clear that I really fucking cared about science and chemistry in particular.
If you can point out that you grok yourself when you look at your hand and think about everything in it, your chances go way up.

hey /sci/
i'm a 17year old doing his as levels and we've just got our physics course work :/
i need a title with the basis "why is material(material/compound/element) X used for the purpose Y" eg: why is copper used for electrical wiring
it need to be fairly normal (not einsteinium or Mendelevium etc) but i want something thats not only going to be easy but will impress but professor...any ideas?
TL:DR; ideas for physics coursework.
pic; un-related.

>>1720591
>>1720591
this is incorrect.

Thought patterns are who you are yet you can control them. Who are "you" /sci/ ?

How about some nerdy jokes?

Pic related

What if a myth can be usefully applied in practice. you don`t know how and why, but there seems to be something usefull (and maybe true) about the myth.

Believing appairs to be the destiny of a human, so why swim against the tie and fallow a verry unlikely logic.

- free will
- why there is good/bad
- gives people peace
sceince can not say anything about the subjects abouve.
Only a theorie which explains all these things abouve can replace the idea of a god.

Pic unrelated.

How is 2*cos(t/2)*sin(t/2) = sin(t)?
:O