1. ## parametric circle

The top half of a circle with center (-7, 8) and radius 9.

the equation for a cirlce, is (x-x1)+(y-y1)=r^2 i think...so then what do i do...help

mer

2. $x = 3\cos (t) - 7,\;y = 3\sin (t) + 8,\;0 \le t \le \pi$

3. The top half of a circle with center (-7, 8) and radius 9.

The whole circle is
(x -(-7))^2 +(y -8)^2 = 9^2
(x +7)^2 +(y -8)^2 = 9^2

The top half of the circle.
That is from y = 8 to y = 17
So,
(x +7)^2 = 9^2 -(y -8)^2
x +7 = +,-sqrt[9^2 -(y -8)^2]
x = +,-sqrt[9^2 -(y -8)^2] -7 ----------***
for only
8 <= y <= 17