Question

integral of cos(3x-5)^2

Answer 1

use double angles rules

Answer 2

cos2x=2cosx-1 .. did you get it ?

Answer 3

and what about the cos^2

Answer 4

sry cos2x=2cosx^2-1

Answer 5

Recall the double angle identity for cosine.
\[\cos(2 \alpha )=\cos^2(\alpha)-\sin^2(\alpha)=\cos^2(\alpha)-(1-\cos^2(\alpha))\]
\[\cos(2 \alpha)=\cos^2(\alpha)-1+\cos^2(\alpha)\]
\[\cos(2 \alpha)=2 \cos^2(\alpha)-1\]
Solve this equation for cos^2(alpha):
\[\cos^2(\alpha)=\frac{1}{2}(1+\cos(2 \alpha))\]

Answer 6

Thank you Amrmagdy and Myininaya :D

Answer 7

urw