Question

What is the integral of `int (2x-sinx) / (x^2 + cosx)`?

Answer 1

Let `x^2 + cosx=t`

`(2x - sinx) dx = dt`

Replace in the original question.
`int (2x-sinx) / (x^2 + cosx)dx = int dt/t`

Again, replace.
`=>log|t| +c = log|x^2 + cosx| + c`