Chapter 3 - Radian Measure and the Unit Circle - Section 3.1 Radian Measure - 3.1 Exercises - Page 105: 85

$\sqrt3$

Convert the angle measure to degrees to obtain: $=-\frac{14\pi}{3} \cdot \frac{180^o}{\pi} = -14(60)^o=-840^o$ Thus, $\tan{(-\frac{14\pi}{3})} = \tan{(-840^o)}$ $-840^o$ is co-terminal with $-840^o+1080^o=240^o$. $240^o$ is in Quadrant III so its reference angle is $=240^o-180^o=60^o$. Note that the tangent function is positive in Quadrant III.