Question

Find the terminal point on the unit circle determined by 7pi//6 radians?

Answer 1

$\frac{7 \pi}{6} = \frac{7*180}{6} = 7*30 = 210$

210 we can write it as 210 = 180 + 30.
So 210 has a reference angle  of 30 degree in third quadrant.

So x co-ordinate of terminal point is cos(210) = $\frac{- \sqrt{3} }{2}$

y co-ordinate of terminal point is sin(210) = $\frac{-1}{2}$

So the terminal point is $( \frac{- \sqrt{3} }{2} , \frac{-1}{2} )$