Find the equation of the circle with : `Centre (-a, -b) and radius sqrt(a^2 - b^2)`.

Explanation

Here it is given that center `(h.k)` and radius `r` is given by


`(x-h)^2+(y-k)^2=r^2`
`:.` the equation of the circle with center `(-a,-b)` having radius `sqrt(a^2-b^2)` is given by


`(x+a)^2+(y+b)^2=(a)^2-b^2`


=>`x^2-y^2+2ax+2by+a^2+b^2=a^2-b^2`
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