Q. The equation of family of circles with centre at $(h,\ k)$ touching the $x$-axis is given by
A) $x^{2} + y^{2} - 2hx + h^{2} = 0$
B) $x^{2} + y^{2} - 2hx - 2ky + h^{2} = 0$
C) $x^{2} + y^{2} - 2hx - 2ky - h^{2} = 0$
D) $x^{2} + y^{2} - 2hx - 2ky = 0$
Explanation
(b)
Required equation is
$(x - h)^{2} + (y - k)^{2} = k^{2}$
$\Rightarrow \ x^{2} + y^{2} - 2hx - 2ky + h^{2} = 0$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.