Question

Question #6c7c0

Answer 1

`2(cos(x/2))^2=1+cosx`

Explanation:

Identity: `cos2A=2cos^2A-1`

`cosx=cos(2*x/2)=2cos^2(x/2)-1=2(cos(x/2))^2-1`

`therefore2(cos(x/2))^2=1+cosx`