Question

How do you simplify `2(cos^2) 5 theta - 1`?

Answer 1

= cos (10t)

Explanation:

Use the trig identity:
`1 + cos 2a = 2cos^2 a`
In this case a = 5t. There for:
`2cos^2 (5t) = 1 + cos (10t)`

`2cos^2 (5t) - 1 = cos (10t)`