## Precalculus: Concepts Through Functions, A Unit Circle Approach to Trigonometry (3rd Edition)

Consider the trigonometry identity: $\sin^2 \theta+\cos^2 \ \theta=1$ Subtract $\cos^2 \ \theta$ from both sides to obtain: $\sin^2 \theta=1-\cos^2 \theta$ Therefore, the given statement is True.