## Trigonometry 7th Edition

$\csc\frac{7\pi}{4}$ = -$\sqrt 2$
Recall: $\csc\theta$ = $\frac{1}{\sin\theta}$ Recall Definition 3: $\sin\theta$ = y Substitute: $\csc\frac{7\pi}{4}$ = $\frac{1}{\sin\frac{7\pi}{4}}$ $\csc\frac{7\pi}{4}$ = $\frac{1}{\frac{-\sqrt 2}{2}}$ $\csc\frac{7\pi}{4}$ = $\frac{1}{1} \times \frac{2}{-\sqrt 2}$ $\csc\frac{7\pi}{4}$ = $\frac{2}{-\sqrt 2} \times (\frac{\sqrt 2}{\sqrt 2})$ $\csc\frac{7\pi}{4}$ = $\frac{2\sqrt 2}{-2}$ $\csc\frac{7\pi}{4}$ = $-\sqrt 2$