In each of the following, find the equation of the circle with
Centre (–2,3) and radius 4
The equation of a circle with centre (h,k) and radius r is given as
(x-h)2 + (y-k)2=r2
It is given that centre (h,K) = (-2,3) and radius (r) =4
Therefore, the equation of the circle is
(x+2)2 + (y-3)2 = (4)2
⇒ x2 + 4x + 4 + y2 - 6y + 9 = 16
⇒ x2 + y2 + 4x - 6y - 3 = 0
Therefore, the equation of the circle is x2 + y2 + 4x - 6y - 3 = 0