Quick math question

[LiLRiceBoi]

I havnet done this stuff in years... but my friend just asked me how to integrate 1/(1+x^4) dx

doenst look very hard but i cant remember this stuff. i'm thinking inverse trig?

 

[ucdbiendog]

integration tables 4tw!

 

[upsciLLion]

u-substitution++

 

[Jonitus]

1/x^5 * (1+x^4 - ln|1+x^4|)+C

 

[chuckywang]

Originally posted by: LiLRiceBoi
I havnet done this stuff in years... but my friend just asked me how to integrate 1/(1+x^4) dx

doenst look very hard but i cant remember this stuff. i'm thinking inverse trig?

I guess integration by parts is your answer.

 

[LiLRiceBoi]

Originally posted by: Jonitus
1/x^5 * (1+x^4 - ln|1+x^4|)+C

how did you get that?

 

[chuckywang]

Originally posted by: LiLRiceBoi

Originally posted by: Jonitus
1/x^5 * (1+x^4 - ln|1+x^4|)+C

how did you get that?

TI-89?

 

[LiLRiceBoi]

someone stole mine last year

integrals.wolfram.com gave me this answer...

 

[chuckywang]

Originally posted by: LiLRiceBoi
someone stole mine last year

 

[Jonitus]

Originally posted by: chuckywang

Originally posted by: LiLRiceBoi

Originally posted by: Jonitus
1/x^5 * (1+x^4 - ln|1+x^4|)+C

how did you get that?

TI-89?

Nope. I use calculus everyday, and as such, have had to practically memorize the basic methods of integrating forms of a+bx.

The integral of xdx/(a+bx) is 1/b^2(a+bx-a ln|a+bx|)+C

 

[chuckywang]

Originally posted by: Jonitus

Originally posted by: chuckywang

Originally posted by: LiLRiceBoi

Originally posted by: Jonitus
1/x^5 * (1+x^4 - ln|1+x^4|)+C

how did you get that?

TI-89?

Nope. I use calculus everyday, and as such, have had to practically memorize the basic methods of integrating forms of a+bx.

The integral of xdx/(a+bx) is 1/b^2(a+bx-a ln|a+bx|)+C

But this is the integral of 1/(1+x^4).

btw, what do you do?

 

[LiLRiceBoi]

yeah it's 1/(1+x^4).

how come no one knows how to do it?? lol

 

[chuckywang]

Originally posted by: LiLRiceBoi
yeah it's 1/(1+x^4).

how come no one knows how to do it?? lol

http://integrals.wolfram.com/

Plug it in here. It doesn't tell you how to do it, but it gives you an answer. However, it seems like it's done by partial fractions.

 

[Jonitus]

I know what you're trying to integrate. The example I gave is a basic form like you would see if you consulted a table in a decent text book. That computer-generated answer is crap...about as handy as if you had Mathematica doing it...the program over-complicates it. Look, compare the xdx/a+bx with the equation you need solved...1/(1+x^4)...x=1, a=1, b=1,...what's so confusing here?

See here...first example...just like I said...

Integration tables

 

[LiLRiceBoi]

I got it.

and chuckywang, you obviously didnt read my edit. thanks for the trying though.

 

[James3shin]

partial fractions would be my guess as well.