Question

antiderivative of ∫(1+x)/(1+x^2).

Answer 1

try \(u=1+x^2\)

Answer 2

no, that is a bad idea

Answer 3

^ Why?

Answer 4

try
\[\frac{1}{1+x^2}+\frac{x}{1+x^2}\] that will work nicely

Answer 5

first is one you do with your eyeballs, (i.e. one you have memorized)
second is a mental u - sub

Answer 6

Oh, I see

Answer 7

sorry, @mkmkasim that was an accident :S

Answer 8

is it arctanx + ln|1+x^2| +c

Answer 9

first is right, second you are off by a constant

Answer 10

how?

Answer 11

\(u=1+x^2,\frac{1}{2}du=xdx\)

Answer 12

need a \(\frac{1}{2}\) out front to adjust for the u sub

Answer 13

oh okay I got it. Thanks