Question

How do you evaluate `int cos^3(5x)sin(5x)dx`?

Answer 1

`-1/20cos^4(5x)+C`

Explanation:

`d/(dx)cos^4(5x) = -4 cdot 5 sin(5x)cos^3(5x)` then

`int sin(5x)cos^3(5x)dx = -1/20cos^4(5x)+C`