How to find the reference angle of -11pi/3 ?
Just replace π by 180°\(\boxed{-\frac{11\pi}{3}=-\frac{11*180}{3}=-660^o=60^o}\)
\(- \frac{11 \pi }{3} \\ \\ =- \frac{11*180}{3} \\ \\ =- \frac{1980}{3}\)\(=-660\) °= 60 °
