Question

How do you simplify `cos^2theta-2sin (2theta )` using the double angle identities?

Answer 1

`cos^2 theta-4sin theta cos theta`

Explanation:

From the given `cos^2 theta-2*sin (2theta)`
we can change the `sin 2theta`

We know that
`sin 2theta=2*sin theta cos theta`

`cos^2 theta-2*sin (2theta)`

`cos^2 theta-2*2*sin theta cos theta`

`cos^2 theta-4sin theta cos theta`

God bless....I hope the explanation is useful.