Question:
Find the equation of the circle with centre (0, 2) and radius 2
Solution:
The equation of a circle with centre (h, k) and radius r is given as
$(x-h)^{2}+(y-k)^{2}=r^{2}$
It is given that centre (h, k) = (0, 2) and radius (r) = 2.
Therefore, the equation of the circle is
$(x-0)^{2}+(y-2)^{2}=2^{2}$
$x^{2}+y^{2}+4-4 y=4$
$x^{2}+y^{2}-4 y=0$