Question

Find the value of $\sin (-11\pi /3)$ ?

Answer 1

$\sin (2\pi -\theta )=-\sin \theta$

$\sin [-\frac{11\pi }{3}]=\sin [2\pi -\frac{11\pi }{3}]=\sin \left[\frac{-5\pi }{3}\right]$

$\sin [2\pi -\frac{5\pi }{3}]=\sin \left[\frac{\pi }{3}\right]=\frac{\sqrt{3}}{2}$