JEE Main & Advanced Sample Paper JEE Main - Mock Test - 33

  • question_answer
    The greatest and least value of sin x cos x are

    A) \[1,\,\,-1\]          

    B)        \[\frac{1}{2},\,\,-\frac{1}{2}\]

    C) \[\frac{1}{4},\,\,-\frac{1}{4}\]    

    D)        \[2,\,\,-\,2\]

    Correct Answer: B

    Solution :

    Let \[f(x)=sin\,x\,cos\,x=\frac{1}{2}sin2x\] We know \[-1\le \sin \,2x\le 1\,\,\Rightarrow \,\,-\frac{1}{2}\le \frac{1}{2}\sin 2x\,\,\le \,\,\frac{1}{2}\] Thus the greatest and least value of f(x) are \[\frac{1}{2}\,\,and\,\,-\frac{1}{2}\] respectively


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