Find the exact value of $\displaystyle sin 2\theta, cos 2\theta, $ and $\displaystyle tan 2\theta$ for the given values of $\displaystyle \theta$

$\displaystyle sec\theta = -3 ; \frac{\pi}{2}$ is greater than $\displaystyle \theta$ or less than $\displaystyle \pi$

Can someone show me how you solve this