# Question #e55db

Feb 1, 2017

$- \frac{3 \sqrt{7}}{8}$

#### Explanation:

$\sin t = \frac{1}{8.}$
Find cos t by using trig identity:
${\cos}^{2} t = 1 - {\sin}^{2} t$
${\cos}^{2} t = 1 - \frac{1}{64} = \frac{63}{64}$
$\cos t = \pm \frac{3 \sqrt{7}}{8}$
Since t is in Quadrant II, then cos t is negative
$\cos t = - \frac{3 \sqrt{7}}{8}$