SSC Sample Paper Mock Test-15 SSC CGL Tear-II Paper-1

  • question_answer
    If \[{{x}^{2}}+{{y}^{2}}+\frac{1}{{{x}^{2}}}+\frac{1}{{{y}^{2}}}=4,\]then the value of\[{{x}^{2}}+{{y}^{2}}\]is

    A) 2

    B)  4    

    C)  8

    D)  16

    Correct Answer: A

    Solution :

    \[{{x}^{2}}+{{y}^{2}}+\frac{1}{{{x}^{2}}}+\frac{1}{{{y}^{2}}}-4=0\] \[\Rightarrow \]   \[{{x}^{2}}+\frac{1}{{{x}^{2}}}-2+{{y}^{2}}+\frac{1}{{{y}^{2}}}-2=0\] \[\Rightarrow \]   \[{{\left( x-\frac{1}{x} \right)}^{2}}+{{\left( y-\frac{1}{y} \right)}^{2}}=0\] \[\Rightarrow \]   \[x-\frac{1}{x}=0\] \[\Rightarrow \]   \[{{x}^{2}}-1=0\] \[\Rightarrow \]\[x=1\] Similarly,           \[y=1\] \[\therefore \]      \[{{x}^{2}}+{{y}^{2}}=1+1=2\]


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