Question

How can we express the x and y-components of a vector in terms of its magnitude, a, and direction, global angle theta?
A. x=acos(theta), y=asin(theta)
B. x=asin(theta), y=acos(theta)
C. x=atan(theta), y=a/cos(theta)
D. x=a/cos(theta), y=atan(theta)