Question

What is `int sin x/ ( 1-sin^2x)dx`?

Answer 1

`1-sin^2x = cos^2x` and `d/dx(cosx) = -sinx`

Explanation:

Rewrite as

`int sin x/ ( 1-sin^2x)dx = int sinx/cos^2x dx`

Now use substitution with `u = cosx`.

Or use the fact that `sinx/cos^2x = secx tanx = d/dx(secx)`