JEE Main & Advanced Mathematics Functions Question Bank Self Evaluation Test - Relations and Functions-I

  • question_answer
    The range of the function \[f(x)={{x}^{2}}+2x+2\] is

    A) \[(1,\infty )\]

    B)        \[(2,\infty )\]

    C) \[(0,\infty )\]

    D)        \[[1,\infty )\]

    Correct Answer: D

    Solution :

    [d] Let \[f(x)=y={{x}^{2}}+2x+2={{(x+1)}^{2}}+1\] \[y-1={{(x+1)}^{2}}\Rightarrow x+1=\sqrt{y-1}\] \[x=\sqrt{y-1}-1\] Since, \[y-1\ge 0\therefore y\ge 1\] \[\therefore \] range is \[\left[ 1,\infty  \right)\].


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