Solving Trigonometric Equations · Review Exercise 126

Find the exact value.

Find $sin\left(2\theta \right),cos\left(2\theta \right),$ and $tan\left(2\theta \right)$ given $cos\theta =-\frac{1}{3}$ and $\theta$ is in the interval $\left[\frac{\pi }{2},\pi \right].$

Its source prints no answer for this problem, so there's nothing to check against.

OpenStax, Algebra and Trigonometry 2e · §9.5 Solving Trigonometric Equations · Review Exercise 126