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

$1$
We find the right-hand limit as follows: $\lim\limits_{x \to \frac{\pi}{2}^{+}} f(x)=\lim\limits_{x \to \frac{\pi}{2}^{+}} \sin (x) \\=\sin (\dfrac{\pi}{2}) \\=1$