Question

Question #8f299

Answer 1

`sin(theta)/4 + theta/2 + cte`

Explanation:

Use the duplication formula :
`cos(2 theta) = 2 cos^2(theta) -1`
therefore
`cos^2(theta) = (cos(2theta) + 1)/2`
(we have "linearised" `cos^2(theta)`)

Now, you can easily integrate :
`int cos^2(theta) d theta = 1/2 int (\cos(2 theta) + 1)d theta = 1/2 [sin(2theta)/2 + theta] + cte`