Find the equation of the circle with radius 5 whose centre lies on x-axis & passes through the point (2,3)?
GIVEN: r = 5
c(2,3)
centre lie on x-axis
i.e c(a,0)
A.T.Q
eq. (2-h)2 + (3-k)2 = 25 ----------------(1)
= (2-a)2 + y2 =25 -----------------------(2)
= 4 - 4a + a2 = 25
= a2 - 4a - 21 =0
= (a-6) (a + 2) =0
therefore a=6 or a= -2
hence
eq. a=6
x2 + y2 - 12x + 11= 0 ---------------ans
And a= -2
x2 + y2 + 4X -21 =0 -----------------ans