Find the equation of a circle, the end points of one of whose diameters are A (2, -3) and B(-3, 5).
We know that the equation of a circle, the end points of one of whose diameters are x1, y1 and x2, y2, is given by
(x−x1)(x−x2)+(y−y1)(y−y2)=0.
Here, x1=2, y1=−3 and x2=−3, y2=5.
∴ the required equation of the circle is
(x−2)(x+3)(y+3)(y−5)=0.
⇒ x2+y2+x−2y−21=0.