Question

Integration again.

Answer 1

\[\int\limits_{}^{} \frac{ x }{ 1 + x^2 }\]

Answer 2

dx...

Answer 3

I can see it fits the form for the derivative of arctan x, but that x on the top is confusing me.

Answer 4

u=1+x^2

Answer 5

@amistre64

Answer 6

Ok

Answer 7

by parts seems fair

Answer 8

or, since 2x is the derivative of the bottom ... mutliply by 2/2 to get a useful 2 out of it

Answer 9

u=1+x^2
du=2xdx

\[\frac{ 1 }{ 2 } \int\limits \frac{ 1 }{ u }du\]

Am I missing something here?

Answer 10

the subsitution is fine :)

Answer 11

Alright, was wondering why over complicate the problem :P

Answer 12

integration is a bit of an art ... which is why its not always so simple to see something on the first pass.

Answer 13

You're right!

Answer 14

Ohh, I see. Then I get as my final answer (1/2)ln(x^2 + 1) + C.
Thanks, I was making the wrong substitution. :p xD

Answer 15

;) we all do at times