SSC Sample Paper SSC CHSL (10+2) Sample Test Paper-6

  • question_answer
    .If \[X=\frac{\sqrt{3\,}+\sqrt{2}}{\sqrt{3}-\sqrt{2}}\] and y = \[Y=\frac{\sqrt{3\,}-\sqrt{2}}{\sqrt{3}+\sqrt{2}}\] Then \[{{x}^{2}}+{{y}^{2}}=?\]

    A)  100                             

    B)  88

    C)  96                   

    D)         98

    Correct Answer: D

    Solution :

     \[x=\frac{\sqrt{3}+\sqrt{2}}{\sqrt{3}-\sqrt{2}}=\frac{\sqrt{3}+\sqrt{2}}{\sqrt{3}-\sqrt{2}}\] \[\times \frac{\sqrt{3}+\sqrt{2}}{\sqrt{3}-\sqrt{2}}=\frac{(\sqrt{3}+\sqrt{{{2}^{2}})}}{(\sqrt{3{{)}^{2}}-(\sqrt{2{{)}^{2}}}}}\]             \[=\frac{3+2+2\sqrt{3\,}\sqrt{2}}{3-2}=5+2\sqrt{6}\] Similarly, we have \[y=5-2\sqrt{6}\] \[\therefore \] \[x+y=10\]  and \[xy=25-24=1\]  \[\therefore \]\[{{x}^{2}}+{{y}^{2}}={{(x+y)}^{2}}-2\times y\] \[={{(10)}^{2}}-2\times 1=100-2=98\]


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