Question

Simplify the following expression by using the double-angle formula.

(Expression inside)

Answer 1

\[cos^25ø-sin^25ø\]

Answer 2

cos(10x) ???

Answer 3

Recall that \(\large \cos^2\alpha - \sin^2\alpha = \cos(2\alpha)\). In this case, \(\large\alpha = 5\theta\), so what do you get as the simplified trig function?

Answer 4

Well, cos(10ø) to be consistent?

Answer 5

And I see you answered it as I was writing up my answer. You are correct. :-)

Answer 6

Thank you.