JEE Main & Advanced Mathematics Circle and System of Circles Question Bank Equations of circle, Geometrical problems regarding circle

  • question_answer
     If \[(\alpha ,\beta )\]is the centre of a circle passing through the origin, then its equation is                                         [MP PET 1999]

    A)            \[{{x}^{2}}+{{y}^{2}}-\alpha x-\beta y=0\]

    B)            \[{{x}^{2}}+{{y}^{2}}+2\alpha x+2\beta y=0\]

    C)            \[{{x}^{2}}+{{y}^{2}}-2\alpha x-2\beta y=0\]

    D)            \[{{x}^{2}}+{{y}^{2}}+\alpha x+\beta y=0\]

    Correct Answer: C

    Solution :

               Radius = Distance from origin \[=\sqrt{{{\alpha }^{2}}+{{\beta }^{2}}}\]                    \[\therefore \] \[{{(x-\alpha )}^{2}}+{{(y-\beta )}^{2}}={{\alpha }^{2}}+{{\beta }^{2}}\]                    \[\Rightarrow {{x}^{2}}+{{y}^{2}}-2\alpha x-2\beta y=0\].


You need to login to perform this action.
You will be redirected in 3 sec spinner