Question

Reduce cos2(6u) to a trigonometric function raised to the first power.

Answer 1

Remember that:
\[
\cos(2x)=\cos^2(x)-\sin^2(x)
\]And, of course:
\[
\sin^2(x)+\cos^2(x)=1
\]See how you can manipulate this to get a useful formula.

Answer 2

sorry it should be \[\cos ^{2}\left( 6u \right)\]

Answer 3

but maybe I'm blind because I don't see how to reduce it to the first power

Answer 4

Let me help you out a bit:
\[
\cos(2x)=\cos^2(x)-\sin^2(x)=\cos^2(x)-(1-\cos^2(x))=2\cos^2(x)-1
\]Use this to reduce the power.

Answer 5

would I put that into the power reducing formula?