Equation of director circle of circle {x^2} + {y^2} = {a^2}, is

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10-1.Circle and System of Circles

easy

The equation of director circle of the circle ${x^2} + {y^2} = {a^2},$ is

A

${x^2} + {y^2} = 4{a^2}$

B

${x^2} + {y^2} = \sqrt 2 {a^2}$

C

${x^2} + {y^2} - 2{a^2} = 0$

D

None of these

Solution

(c) Director circle has its radius $\sqrt 2 $ times that of radius of the given circle.

Hence equation is ${x^2} + {y^2} = 2{a^2}$.

Standard 11

Mathematics

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