/sci/ - Science & Math » Thread #12429926

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Anonymous Mon 07 Dec 11:22:25 2020 No.12429926 View Reply Original Report

Quoted By: >>12429936 >>12429939 >>12429956 >>12429958 >>12429966 >>12429974 >>12429985 >>12429992 >>12430199

Hi anons, I'm at uni and need to learn integrals in the next 20 hours, otherwise I'm fucked.
Assume I only know elementary 2+2=4 and basic functions.
Is there a tutorial from zero to hero, or a list of subjects that I need to learn?

Anonymous

Anonymous Mon 07 Dec 2020 11:28:46 No.12429936 Report

Quoted By: >>12429957

>>12429926
Go on Khan academy and nerd the course on integrals, if you want there is one for calculus in general too.

Why do you need to learn it so quickly?

Cramming is bad for learning.

Anonymous

Anonymous Mon 07 Dec 2020 11:30:36 No.12429939 Report

Quoted By: >>12429995

>>12429926
Yeah go to wolframalpha or symbolab.

Anonymous

Anonymous Mon 07 Dec 2020 11:39:39 No.12429956 Report

Quoted By: >>12429994

>>12429926
do what all faggots do
memorize the table of integrals, learn integration by parts and by substitution, and you'll be fine.
> a hint
> make a table based on derivatives which look like this
$\frac{d}{dx} (x^2) = 2x \implies d(x^2) = 2xdx$
so if you see in your integral something like this
$\frac{2x}{\sqrt{1 + x^2}}dx$
notice the 2x dx which implies substitution
$u = x^2$

Anonymous

Anonymous Mon 07 Dec 2020 11:40:13 No.12429957 Report

Quoted By: >>12429994 >>12429995

>>12429936
Just to finish some assignments. I'll take proper time to learn it after that.

Alright thanks

Anonymous

Anonymous Mon 07 Dec 2020 11:40:57 No.12429958 Report

Quoted By: >>12429968

>>12429926
ok, you know derivatives that you learned last semester? Just do that backwards. DONE.

Anonymous

Anonymous Mon 07 Dec 2020 11:45:46 No.12429966 Report

Quoted By:

>>12429926
Pick any integrals course in youtube and you're ready to go

Anonymous

Anonymous Mon 07 Dec 2020 11:47:21 No.12429968 Report

Quoted By: >>12429990

>>12429958
We had derivatives last week, but I know literally nothing about math, lmao. Hopefully I can use my supreme homo sapiens intelligence and learn everything in a few days.

Anonymous

Anonymous Mon 07 Dec 2020 11:49:46 No.12429974 Report

Quoted By: >>12429997

>>12429926
Just (x^(n+1))/(n+1)

Anonymous

Anonymous Mon 07 Dec 2020 11:55:47 No.12429985 Report

Quoted By: >>12429989

>>12429926
>I'm at uni
what uni? engineering?

Anonymous

Anonymous Mon 07 Dec 2020 11:56:48 No.12429989 Report

Quoted By: >>12429997

>>12429985
Physics

Anonymous

Anonymous Mon 07 Dec 2020 11:57:41 No.12429990 Report

Quoted By: >>12430024

>>12429968
>We had derivatives last week, but I know literally nothing about math, lmao. Hopefully I can use my supreme homo sapiens intelligence and learn everything in a few days.

$\int f(x) dx = F(x) + C$
C is a number
F is related to f
$\frac{d}{dx} (F(x) + C) = f(x)$
Derivative of a constant is 0. F is even called an antiderivative.
Therefore
if $\frac{d}{dx} (x^2) = 2x$ then
$\int 2x dx = x^2 + C$
ofc, this doesn't say much about what you are truly doing, but it's enough to pass some mindless test

Anonymous

Anonymous Mon 07 Dec 2020 11:58:05 No.12429992 Report

Quoted By:

>>12429926
there are two types of integration. Numerical and analytical.

There are two types of analytical integration. Definite and Indefinite.

Anonymous

Anonymous Mon 07 Dec 2020 11:58:49 No.12429994 Report

Quoted By: >>12430024

>>12429956
This will not help a retard at all.

>>12429957
If it's only for an assignment just do it on an integral calculator as other anon said. There are some which give you the derivation also. On the long run you can watch 3b1b videos for basic intuition, then do a ton of examples until you just look at a function and know within 3 secs how to integrate it.

Anonymous

Anonymous Mon 07 Dec 2020 11:59:02 No.12429995 Report

Quoted By: >>12430024

>>12429957
>Finish some assignments. I'll take proper time to learn after that.
Legit do this >>12429939. They even go theough steps as well. You won't fully learn from just that be it gets the job done and you said you'd properly learn them later.

Anonymous

Anonymous Mon 07 Dec 2020 12:00:18 No.12429997 Report

Quoted By: >>12430003 >>12430012

>>12429989
all right, so given a function you just expand it into a quadratic taylor polynomial (physicists don't care about higher orders anyway) and integrate using >>12429974

Anonymous

Anonymous Mon 07 Dec 2020 12:02:55 No.12430003 Report

Quoted By:

>>12429997
> implying this wasn't a joke
he's gonna get confused where to make the taylor expansion kek.

Anonymous

Anonymous Mon 07 Dec 2020 12:13:22 No.12430012 Report

Quoted By:

>>12429997
What do you mean physicists dont care about higher orders?

Anonymous

Anonymous Mon 07 Dec 2020 12:20:18 No.12430024 Report

Quoted By: >>12430057

>>12429995
>>12429994
Got it!

>>12429990
Okay, looks relatively easy.

Anonymous

Anonymous Mon 07 Dec 2020 12:36:01 No.12430057 Report

Quoted By: >>12430196

>>12430024
>Okay, looks relatively easy.
sometimes there are tricks involved. not all integrals are super easy, though I doubt any first course will bother to ask for some hard integrals.
A neat trick can be done with some integrals like this
$\int \ln x dx = \int 1\cdot \ln x dx = x\ln x - \int x \cdot \frac{1}{x} dx = x \ln x - x + C$
or
$\int \sin^2 x dx = \int 1 \cdot \sin^2 x dx = x \sin^2 x - \int x \cdot 2 \sin x \cos x dx = x \sin^2 x - \int x \cdot \sin (2x) dx = x \sin^2 x - \int \frac{u}{2} \cdot \sin (u) \frac{1}{2}du = x \sin^2 x - \frac{1}{4} \int u\cdot \sin (u)du = x \sin^2 x - \frac{1}{4}\left[ -u \cos u - \int \sin u du \right ] =$
> I have no fucking idea if I done it right, since I've done it in the postbox on 4chan kek

Anonymous

Anonymous Mon 07 Dec 2020 13:41:20 No.12430187 Report

Quoted By:

This might help. https://www.integral-calculator.com/

Anonymous

Anonymous Mon 07 Dec 2020 13:46:55 No.12430196 Report

Quoted By:

>>12430057
Phone posters hate you

Anonymous

Anonymous Mon 07 Dec 2020 13:52:13 No.12430199 Report

Quoted By:

>>12429926
how the fuck can you be at uni without knowing derivatives let alone integrals lmao ?
is this the power of america the best country of the world ?

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