Chapter 4.2, Problem 22PE

In Exercises 5-18, the unit circle has been divided into twelve equal arcs, corresponding to t-values of

$0,\frac{\pi }{6},\frac{\pi }{3},\frac{\pi }{2},\frac{2\pi }{3},\frac{5\pi }{6},\pi ,\frac{7\pi }{6},\frac{4\pi }{3},\frac{3\pi }{2},\frac{5\pi }{3},\frac{11\pi }{6},\text{and}2\pi$

Use the (x, y) coordinates In the figure to find the value of each trigonometric function at the indicated real number, t, or stale that the expression is undefined.

In Exercises 19-24,

a. Use the unit circle shown for Exercises 5-18 to find the value of the trigonometric function.

b. Use even and odd properties of trigonometric functions and your answer from part (a) to find the value of the same trigonometric function at the Indicated seal number.

a. $\sin \frac{2\pi }{3}$

b. $\sin \left(-\frac{2\pi }{3}\right)$