Geometry
# Sum and Difference Trigonometric Formulas

Given that $\sin^2 \theta = \frac{1}{3}$, what is the value of $72 \cos(2 \theta)$?

The double angle identity states that

$\cos (2 \theta) = N \cos^2 \theta - M,$

where $N$ and $M$ are real numbers. What is the value of $N + M$?

The double angle identity states that

$\sin ( 2 \theta ) = N \sin \theta \cos \theta + M,$

where $N$ and $M$ are real numbers. What is the value of $N + M$?