Find the equation of a circle whose centre is (3, -1) and which cuts off a chord of length 6 units on the line 2x−5y+18=0.
Distance from centre O(3,−1) to the line 2x−5y+18=0 is OE=6+5+18√22+(−5)2
=29√4+25
∴OE=√29
From triangle ΔOEA
AO2=OE2+AE2
=9+29
∴AO=√38, which is the radius of the circle.
Equation of circle with centre (3, -1) and radius as √38 is
(x−3)2+(y+1)2=(√38)2
x2−6x+9+y2+2y+1=38
x2+y2−6x+2y=28