# How do you solve sin (Arccos (7/25))?

Jun 21, 2016

$\pm \frac{24}{25}$

#### Explanation:

Use $\cos \left(- \theta\right) = \cos \theta$.

Let $a = a r c \cos \left(\frac{7}{25}\right)$. The $\cos a = \frac{7}{25}$. a is in either 1st

quadrant or is in the fourth. Accordingly, the given expression

$\sin a = \pm \sqrt{1 - {7}^{2} / {25}^{2}} = \pm \frac{24}{25}$. .