Question

How do you find the antiderivative of `cos 5 x`?

Answer 1

`1/5 sin 5x +C`

Explanation:

Anti derivative of `cos 5x` means `int \ cos 5x \ dx`

Now, let `5x=t`, so that `5 dx=dt` or, `dx =1/5 dt`

Thus `int \ cos 5x \ dx =1/5 int \ cos t \ dt`

`=1/5 sint +C`

`=1/5 sin5x +C`