JCECE Engineering JCECE Engineering Solved Paper-2010

  • question_answer
    Minimum value of\[{{4}^{x}}-{{4}^{1-x}},\,\,x\in R\]is

    A) \[1\]                                     

    B) \[2\]

    C) \[3\]                                     

    D) \[4\]

    Correct Answer: D

    Solution :

    We know that,\[AM\ge GM\] Therefore, for\[{{4}^{x}}\]and\[{{4}^{1-x}}\], we have                 \[\frac{{{4}^{x}}+{{4}^{1-x}}}{2}\ge \sqrt{{{4}^{x}}\cdot {{4}^{1-x}}}\] \[\Rightarrow \]               \[{{4}^{x}}+{{4}^{1-x}}\ge 2\sqrt{4}\] \[\Rightarrow \]               \[{{4}^{x}}+{{4}^{1-x}}\ge 4\] Hence, minimum value of\[{{4}^{x}}+{{4}^{1-x}}\]is\[4\].


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