Sketch each circle on your paper, and label the center and the radius. For a-d, rewrite the equation as two functions. Use your calculator to check your work.
a. x2 + y2 = 4
b. (x - 3)2 + y2 = 1
c. (x + 1)2 + (y - 2)2 = 9
d. x2 + (y - 1.5)2 = 0.25
e. x = 2 cos t + 1
y = 2 cos t + 2
f. x = 4 cos t - 3
y = 4 sin t