Find the coordinates of the centre radius of each of the following circle:
x2 + y2 – ax – by = 0
Given:
equation of the circle is x2 + y2 - ax - by = 0 .... (1)
We know that for a circle
x2 + y2 + 2ax + 2by + c = 0 .... (2)
⇒ Centre = (- a, - b)
⇒ Radius = 
Comparing (1) with (2) we get,
⇒ Centre = 
⇒ Centre = 
⇒ Radius = 
⇒ Radius = 
⇒ Radius = 
⇒ Radius = 
∴ The centre and radius of the circle is 
and 
.
1