Chapter 7 - Section 7.3 - Double-Angle, Half-Angle, and Product-Sum Formulas - 7.3 Exercises - Page 561: 8

$sin2x=-\frac{\sqrt 3}{2}$ $cos2x=-\frac{1}{2}$ $tan2x=\sqrt 3$

$cos(x)=\frac{1}{sec(x)}=\frac{1}{2}$, $x$ is in Quadrant IV, $sin(x)=-\frac{\sqrt 3}{2},tan(x)=-\sqrt 3$ $sin2x=2sin(x)cos(x)=-\frac{\sqrt 3}{2}$ $cos2x=2cos^2x-1=-\frac{1}{2}$ $tan2x=\frac{sin2x}{cos2x}=\sqrt 3$