CET Karnataka Engineering CET - Karnataka Engineering Solved Paper-2000

  • question_answer
    The equation of a circle parsing through (1, 0) and (0, 1) and having smallest possible radius is:

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

    B)  \[{{x}^{2}}+{{y}^{2}}+x+y=0\]

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

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

    Correct Answer: A

    Solution :

    The standard equation of circle\[{{x}^{2}}+{{y}^{2}}+2gx+2fy+c=0,\] equation of the circle passing through (1, 0) is \[1+2g+c=0...(i)\]equation of the circle passing through (0, 1) is\[1+2f+c=0...(ii)\] since both the circles pass through the origin (0, 0) therefore\[c=0...(iii)\] equation (i), (ii) and \[(iii),g=-1/2,\]\[f=-1/2,c=0\]                 \[{{x}^{2}}+{{y}^{2}}-x-y=0\]


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