Intergrate the following:
`intcos2xcos(x/2)dx`

Explanation

`intcos2xcos(x/2)dx`
= `1/2 int2cos2x.cos(x/2)dx`
`1/2 int{cos((5x)/2)+cos((3x)/2)}dx`
= 1/2 . 2/5sin((5x)/2)+1/2 . 2/3sin((3x)/2)+C
=1/5sin((5x)/2)+1/3sin((3x)/2)+C