If the center is (0, 0), then there is no side to side or up or down motion. The center is at the origin. The standard form of a circle is (x-h)^2 + (y-k)^2 = r^2. Your h and your k are both 0's, so just fill in and square the radius:
x^2 + y^2 = 64
Answer:
5 x (4+y)
Step-by-step explanation:

Using the fact that cos is 2π-periodic, we have

That is,
for any
and integer
.

We get 2 solutions in the interval [0, 2π] for
and
,

They each get half a slice of pizza