## Trigonometry (11th Edition) Clone

$x=-\frac{\sqrt 3}{ 2}$
Given: $6$ $arccos$ $x=5\pi$ $arccosx=\frac{5\pi}{6}$ (Divide by 6) Apply definition of arccosine. $x=cos(\frac{5\pi}{6})$ Hence, $x=-\frac{\sqrt 3}{ 2}$