Find the equation of a circle with centre (2, -3) and rad...
Find the equation of a circle with centre (2, -3) and radius 2 units.
x2+y2−4x+6y+9=0
x2+y2+4x−6y−9=0
x2+y2+4x+6y−9=0
x2+y2+4x−6y+9=0
Correct answer is A
The equation of a circle with centre coordinate (a, b) and radius r is :
(x−a)2+(y−b)2=r2
Given centre = (2, -3) and radius r = 2 units
Equation = (x−2)2+(y−(−3))2=22
x2−4x+4+y2+6y+9=4
x2+y2−4x+6y+4+9−4=0⟹x2+y2−4x+6y+9=0