Question

How do you rewrite cos^2 x - (1/2) using double angle formula? Thank you.

Answer 1

See below.

Explanation:

`cos^2(x)-1/2`

Add:

`(2cos^2(x)-1)/2`

Identity:

`color(red)bb(cos(2x)=2cos^2(x)-1)`

Substituting:

`(cos(2x))/2`

`1/2cos(2x)`