Help with calculus please

Question

Consider the following.

t= 31π/6

(a) Find the reference number t for the value of t.

t=

(b) Find the terminal point determined by t.

(x,y)=

Answer 1

(a) 31π/6 = 51/6π, and because reference angle is: 51/6π - 4π = 11/6π = 7/6π.

7/6π in quadrant III, so reference number t = 7/6π - π = π/6;

(b) x = cos31π/6 = - cosπ/6 = - √3/2; y = sin31π/6 = - sinπ/6 = - 1/2; (x, y) = (- √3/2, - 1/2)