JEE Main & Advanced Mathematics Equations and Inequalities Question Bank Self Evaluation Test - Linear Inequalities

  • question_answer
    If \[{{(\sqrt{2})}^{x}}+{{(\sqrt{3})}^{x}}={{(\sqrt{13})}^{x/2}},\] then the number of values of x is

    A) 2

    B) 4

    C) 1

    D) None of these

    Correct Answer: C

    Solution :

    [c] \[{{2}^{x/2}}+{{3}^{x/2}}={{(\sqrt{13})}^{x/2}}\] \[\Rightarrow {{\left( \frac{2}{\sqrt{13}} \right)}^{x/2}}+{{\left( \frac{3}{\sqrt{13}} \right)}^{x/2}}=1\] Which is of the form \[{{\cos }^{x/2}}\alpha +{{\sin }^{x/2}}\alpha =1.\] \[\therefore \,\,\,\,\,\frac{x}{2}=2.\]


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