## Algebra 2 (1st Edition)

Use the Identity $2 \cos^2 \theta =1+ \cos 2 \theta$ Use the correct identity $\cos 2 \theta=1+\cos 2 \theta$ or, $2 \cos^2 \theta=1+ 2 \cos^2 \theta-1$ $2 \cos^2 \theta=2 \cos^2 \theta$ Hence, the result has been verified.