# If cos(x) = (1/4), where x lies in quadrant 4, how do you find sin(x)?

Jun 23, 2016

$\sin x = - \frac{\sqrt{15}}{4}$
$\sin x = \pm \sqrt{1 - {\cos}^{2} x}$
$\sin x = - \sqrt{1 - \frac{1}{16}} = - \sqrt{\frac{15}{16}} = - \frac{\sqrt{15}}{4}$