Question #8f299

1 Answer
Oct 19, 2017

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