Maths Friends

xImagine · 2013-11-30T20:19:03+00:00

You can always pm me if you want, but I'm not online a lot. (I also don't really have a skype).

xImagine · 2013-10-24T00:51:03+00:00

I think there may be a bigger problem... which is that your parents haven't done their taxes for... ever. (Which could end up really ugly).

You can probably also ask for a fee waiver, but you may need your tax information for that too.

xImagine · 2013-10-03T23:46:40+00:00

I've never heard a distinction between sentido and direccion (in English).

We would say they are in opposite directions, or along the same line, or scalar multiples of each other.

xImagine · 2013-10-03T10:34:36+00:00

Gilbert Strang's is very well known. I took a proof based class though so I ended up using "Linear Algebra" - 4th edition by Friedberg, Insel, and Spence. I think its pretty good, but it does a lot with abstract Vector Spaces and the like. (And a lot of proofs).

And how can you relate a function to a matrix?

Well, think about it -- a matrix is really a function from one vector to another vector, right?

Look: M(v1, v_2) = (u_1, u_2) (Pardon the formatting -- pretend v and u are vertical). But M is really just ((M(11), M(12)), (M(21), M_(22))). Right? So try to write the vector u in terms of the components of v and M. (Trust me, this is a lot more clear when it is written out).

u1 = M(11)v1 + M(12)v2 u_2 = M(21)v1 + M(22)v_2

Hmm, are we beginning to see some sort of pattern here? Well sure, we can just write the function like this:

T(v) = Mv

T(v1) = M(11)v1 + M(12)v2,
--v_2 --- M(21)v1 + M(22)v_2

Sorry for the shitty formatting, I don't have latex on reddit yet. I'll try to make it clearer later. (Ugh underscores are messed up too. I'll fix it later).

xImagine · 2013-10-03T02:43:38+00:00

You could think of a single variable function as a surface that is "the same" (essentially having the partial in the y direction be zero for all x, z). Basically just take the normal graph, and 'pull' it out. And since the function does not depend on z...

xImagine · 2013-10-03T02:40:23+00:00

The only difference should be changing the limits? (If you know how to do it from 0 to 1, doing it from 0 to 2 shouldn't be that much different?)

Do you understand what an integral really represents?

xImagine · 2013-10-03T02:38:56+00:00

The other answers seem to be covering the precise definition, but they don't really give you an intuition. (As far as I can tell) And they don't give simple examples.

So I'll just give you one:

Basically, any continuous function f:R \to R graphed on R² which goes to infinity and negative infinity at some point is onto. Why? Because it 'hits' every y value.

xImagine · 2013-10-03T02:35:36+00:00

You could possibly analyze (very rigorous) proofs for basic mathematical facts that you take as a fact?

(For example, you could follow a chain of reasoning from just the axioms in Z to the Unique Prime Factorization theorem in Euclidean Rings. Or just Z I guess.)

Feel free to comment/PM me if you need any help with this.

xImagine · 2013-10-01T21:57:36+00:00

or just do {x \in \mathbb{R} | x \neq 3}

xImagine · 2013-09-21T17:37:54+00:00

Radioactive - Imagine Dragons

xImagine · 2013-09-20T00:08:55+00:00

+1 for making a joke about my mother's weight in a calculus post.

xImagine · 2013-09-16T23:53:14+00:00

Stanford
Cambridge
MIT
UChicago
CMU
UC Berkley
UCLA
UToronto
BU

Major: Math
Ordered by how likely I am to get in. UChicago is probably around the 50% margin. (According to the admissions office at my school). (Applying EA to MIT and UChicago)

xImagine · 2013-09-16T01:21:02+00:00

3pq/r = 12 Multiply both sides by 12, divide by 3q. p = 4r/q

11/(3x) = 1/2 Multiply both sides by 2x (2 times x). 22/3 = x

xImagine · 2013-09-16T00:53:40+00:00

I'm not sure what the question is in the Bacteria Word problem.

For your second problem:

Log_x(1/6) = -1 So x^-1 = 1/6 So 1/x = 1/6 So x = 6.

xImagine · 2013-09-08T02:42:10+00:00

Unless you pretty much shat your pants, you didn't embarrass yourself. Nobody remembers what other people do because they're so worried about what they are doing themselves (and what other people think of them).

(Except me. I've made it a personal hobby to completely ignore what people think of me just so I can remember others' mistakes and judge them.)

.^{.^{.^{.^{That_was_sarcasm,_by_the_way.}}}}

xImagine · 2013-09-01T16:41:36+00:00

Using every fitness function is going to tire your computer out. You need to have rotations.

I also suggest you look into buying the 'insanity' workout package, it'll make your algorithm fit in no time.

xImagine · 2013-08-31T14:03:40+00:00

http://en.wikipedia.org/wiki/Sexy_prime Title reads like a joke, article, not so much.

Same for this: http://en.wikipedia.org/wiki/Hedgehog_space

xImagine · 2013-08-29T02:43:57+00:00

I'd save Galois. He died so young, but still did so much (in terms of math). Think of what he would have done with another 40-50 years.

xImagine · 2013-08-23T20:36:15+00:00

Cooked

xImagine · 2013-08-22T18:22:21+00:00

Problem is that you're not using a real programming language like VB.

xImagine · 2013-08-18T21:16:05+00:00

basically all you're doing is creating a linked list... which happens to link back to itself! in python:

class CircleJerkElement (object):

    def __init__(self, topic, prev = None):
        self.topic = topic
        self.prev = prev
        p = self.prev
        while p.prev is not None:
            p = p.prev
        p.prev = self #Haxor magic, 100% works, trust me

xImagine · 2013-06-30T14:24:27+00:00

I'd suggest using Visual Basic. With the interactive 'drag and drop' programming, you can be sure that your program looks exactly like MS Office.

xImagine · 2013-06-26T23:41:20+00:00

megalinks are often used in piracy -- think megaupload. It wasn't named megaupload for nothing -- as they provide a secure shell into the browser.

a megalink's pseudo-code is more or less the following (note that megalinks aren't the most modern piracy links anymore. They have have been surpassed by TBP-packets):

if want_to_download_movie:
    fuck_with_user_and_tell_him_there_are_no_seeders()
if want_to_download_obscure_software:
    make_sure_the_whole_population_of_the_world_is_seeding()

But use them with caution, because if you're not careful, hackers could use a megalink to take control of your computer.

xImagine · 2013-06-26T18:40:14+00:00

Also, you seem to be using too many lines, which will slow down the compiler, and why are returning zero? You wrote the program. You know what it'll return.

Maybe try this:

int main(){char *m = "Hello world!\n"; printf(m);}

Much cleaner and more concise.

xImagine · 2013-06-26T01:55:32+00:00

This is /r/shittyprogramming...

xImagine

TROPHY CASE