Question

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

Answer 1

this (almost) looks like u^-1 du

Answer 2

This smells of parts, but I'm having trouble with \[\int\limits \frac{1}{x^2+1}dx\]

Answer 3

that is arctangent

Answer 4

Although that might not help

Answer 5

can you enlighten us with the problem?

Answer 6

Do a substitution \(u=x^2, du=2xdx\)

Answer 7

\[0.5 \ln(u+1)\]

Answer 8

@sirm3d It's halfway through the DE of my last question

Answer 9

Yes. Now make the inverse substitution.

Answer 10

post a link @henpen

Answer 11

http://openstudy.com/users/henpen#/updates/50968019e4b0d0275a3ce47b

Answer 12

hmm, can we try reduction of order with \[y=v(ix)\]