Try substitution.
Let u = sin 8x
du = 8 cos 8x dx
That makes the integral
3 du/(1+u^2)
with limits from u = 1 to -1
That should be an easy one.
(24cos(8x))/(1+(sin^2(8x)))
Integrated from (pi/16,-pi/16
2 answers
Thank you. That made it so much simpler.