determine the formula for the set of all points

Question

a)Determine a formula for the set of all points, P(x, y), whose distance from (−2,2) is 9. (Your answer should not have a square root in it.)

b)This is a circle of radius _____
, with a center at (x, y) =




.

Answer 1

Hi Crestina,

 

Recall the equation for a circle is

 

1) (y-y1)² + (x-x1)² = r² 

 

We get the (x₁,y₁) from the point (-2,2) and r = 9

 

(y-2)² + (x-(-2))² = 9²

(y-2)² + (x+2)² = 9²

y²-4y+4 + x²+4x+4 = 81

x²+y²+4x-4y = 73

 

b) This is a circle of radius 9 with a center at (-2,2).