ask me math questions (srs)

[Spaghettii]

I hate all the Analysis courses I've had to take.

idk...sounds fun getting a taste at pure mathematics. should build up a lot of logical skills

[Merauder]

It is fun getting a taste of pure mathematics

currently reading about linear algebra

seems like a fundamental subject to me

[Spaghettii]

It is fun getting a taste of pure mathematics

currently reading about linear algebra

seems like a fundamental subject to me

its just about vector spaces and the like, isnt it?

[Merauder]

its just about vector spaces and the like, isnt it?

it's surtout about the linear combinations of vectors

like how vectors v1, v2, v3 element of R^3
and scalars a, b, c element of R can make a linear combination
av1 + bv2 + cv3

vectors can be added like this


all of the linear combinations produce a vector space which can be represented as a plane, line, R^3, R^4 or anything else for that matter

just imagine it like 3 vectors in R^3 that are all in the same direction, any linear combination av1 + bv2 + cv3 could only produce the same line
now if only 2 of these vectors are in the same direction then all the linear combinations produce a plane

If the third one is also in a different direction than all the linear combinations produce R^3

small pic but can you see how the linear combinations of the vectors V, W element of R^2 produce the darker shaded plane? (the plane is infinitly large)



the whole matrix representation of vectors is very powerfull imo

Gilbert Strang has lectures on the MITyoutube-channel about linear algebra
but there are more than 30 lectures that take about 45 minutes...

[lift*then*PWN]

Find the line y = ax + b that best fits the data points (x, y) = (1, 1), (0, 1), (1, 2), (2, 2)

y=1/2x+1

[Merauder]

above post ^^

noted

so the vectors v1, v2, v3 I talked about are element of (R^3,+ ,*)
v1 = (3, -1, 5) that is element of R^3 when talking about linear algebra could be interpreted as being element of the vector space (R^3, +, *)

[charity4thepoor]

fffuuuuuuuu i hate pure math

applied math is where the ****s at

[MiscMathematician]

noted

so the vectors v1, v2, v3 I talked about are element of (R^3,+ ,*)
v1 = (3, -1, 5) that is element of R^3 when talking about linear algebra could be interpreted as being element of the vector space (R^3, +, *)

Yes to your first question. Usually vectors with components a,b,c are notated as <a,b,c> or ai+bj+ck to avoid confusion with the point (a,b,c). The vecor <a,b,c> is a directed line segment from the origin to the point (a,b,c).

[sinct84]

whats F' of x+3/8x+1 and F"

[MiscMathematician]

whats F' of x+3/8x+1 and F"

d/dx a*x^n = a*n*x^(n-1)

[whitedwarf]

lol ITT MiscMathematician comes in and styles on everyone with his pure maths and proofz.


MiscMathematician how the fck do you remember some of this sh!t... I am 4th year math major and don't remember anything worth anything... I do a lot of lie algebra now.

[RawJeansSon]

Its an easy proof. In a senior level (400) Real Analysis class you will do things like this and likely more difficult than this. Grad analysis (600/700) is on a whole other level completely. For an intricate treatment of senior undergrad/beginning grad book look at Principles of Mathematical Analysis.

What classes are you suppose to take in 200 or 300 level math?

I'm finishing 2nd year, finished cal 1 (didn't start as science/field).

not sure if i can finish in 4 years if i wanted a math degree

So if I did, in Junior year, I'd be taking calc 2, calc 3, mv, linear algebra

senior:
????

[sinct84]

d/dx a*x^n = a*n*x^(n-1)

lulz what, thats not right.

[MUFC]

lulz what, thats not right.

He didn't give you the answer.

He told you how to get the answer.

[Green54]

Prove that 1+1=2

[MUFC]

Prove that 1+1=2

For any set S, define a "successor" function f as

f(S) = {S, {S}}

Then we define the natural integers as such:

Define the number 0 to be the empty set, which I'll write here as O.

Then each successive integer (ie "n+1") is just the preceding integer put through the successor function, ie

1 = {O, {O}}
2 = {O, {O, {O}}}
3 = {O, {O, {O, {O}}}}

and so on.

Then 1+1=f(1)={O, {O, {O}}}=2. QED

I didn't do this myself.

[SaniK]

Are there different sizes of infinity? Me and a friend got into an argument with him saying that there was... but it doesn't make any sense.

[sinct84]

He didn't give you the answer.

He told you how to get the answer.

thats not how you get the answer either

[MUFC]

Are there different sizes of infinity? Me and a friend got into an argument with him saying that there was... but it doesn't make any sense.

http://en.wikipedia.org/wiki/Cardinality

[charity4thepoor]

Are there different sizes of infinity? Me and a friend got into an argument with him saying that there was... but it doesn't make any sense.

if you take a limit of something and you get say 2infinity/infinity then you just say it approaches 2, horizontal asymptotes for example.

if it is infinity^n/infinity^m

if n>m then it is still infinity
if n<m it is zero

but infinity is just a theoretical number that you can never get to, so there aren't different degrees of it.

[Merauder]

Are there different sizes of infinity? Me and a friend got into an argument with him saying that there was... but it doesn't make any sense.

This has to do with counting the number of elements in a set I think?

cardinality

How N and R both go to infinity but in R there are also infinitly many elements between 0 and 1.

[MUFC]

thats not how you get the answer either

First derivative= (8x^2 -3)/8x^2

Second derivative= 3/4x^3

[tvman]

lulz at MiscMathematician showing everyone up. I'm glad I'm completely done with math.

[Spaghettii]

lulz at MiscMathematician showing everyone up. I'm glad I'm completely done with math.

until what math did you take brah?

[tvman]

until what math did you take brah?

Diff/Multi var calc/linear algebra. Also needed to take a statistics/probability math.

[BrownBear626]

2x+1=5







lol

[Spaghettii]

fffuuuuuuuu i hate pure math

applied math is where the ****s at

yep

d/dx a*x^n = a*n*x^(n-1)

**** it, use the quotient rule

lol ITT MiscMathematician comes in and styles on everyone with his pure maths and proofz.


MiscMathematician how the fck do you remember some of this sh!t... I am 4th year math major and don't remember anything worth anything... I do a lot of lie algebra now.

wtf is lie algebra?

lulz what, thats not right.

power rule or quotient rule, your choice

[Spaghettii]

Diff/Multi var calc/linear algebra. Also needed to take a statistics/probability math.

calculus courses are fun, dunno about linear algebra. what can i use linear algebra for in real life? calculus is easy to use IRL, but linear algebra? rly?

[sinct84]

power rule or quotient rule, your choice

yeah its the quotient rule, i was actually hoping you'd figure it out. It was on a final I had a few weeks ago and for sum reason it just stumped me. I don't recall if that was the exact equation but it was the only thing I got wrong on the exam and they never showed the correct answer

[MaximusMiscimus]

what is the derivative of phone

fixed