Question

Find the equation of the director circle of a circle ` x^2 + y^2 =100.`

Answer 1

Given circle is

`x^2 + y^2= 100`

`therefore a^2 =100`

`a =10`

therefore Equation of director circle is

`x^2 +y^2 =2a^2`

`therefore x^2 + y^2 =200`