The point P(t) = (x,y) is the terminal point on the unit circle. If y = , and x

The point P(t) = (x,y) is the terminal point on the unit circle. If y cos t - and x < 0, find the value of cost. (Simplify pur answer. Type an exact answer, using radicals as needed. Use integers or fractions for any numbers in the expression. Rationalize all denominators.)