Question

How do you find the integral of `int(sinx)/(cos^3(x)) dx?`?

Answer 1

I found: `1/(2cos^2(x))+c`

Explanation:

I would try considering that:
`d[cos(x)]=-sin(x)dx` and write:
`int-(d[cos(x)])/cos^3(x)=` and integrate as if `cos(x)` were a simple `x`;
`=-intcos^-3(x)d[cos(x)]==-cos^-2(x)/-2+c=1/(2cos^2(x))+c`