1. Let x R and let be the radian measure of an angle in standard position.

(a) Choose a value for x. Then let = x and graph .

(b) For any value of x, is it possible to find = x? Explain.

(c) Choose a value for and graph . Is there a real number x that is equivalent to ? Explain.

(d) For any value of , is there a real number x that corresponds to ? (e) Use your work in parts (a)-(d) to jutify the domain of cos() and sin().