RAJASTHAN ­ PET Rajasthan PET Solved Paper-2005

  • question_answer
    The value of\[\underset{x\to 0}{\mathop{\lim }}\,\frac{\sqrt{\left[ \frac{1}{2}(1-\cos 2x) \right]}}{x}\]is

    A)  1              

    B)  \[-1\]

    C)  0              

    D)  None of these

    Correct Answer: D

    Solution :

     \[\underset{x\to 0}{\mathop{\lim }}\,\frac{\sqrt{\left[ \frac{1}{2}(1-\cos 2x) \right]}}{x}\] \[=\underset{x\to 0}{\mathop{\lim }}\,\frac{\sqrt{{{\sin }^{2}}x}}{x}=\underset{x\to 0}{\mathop{\lim }}\,\frac{|\sin x|}{x}\] \[\therefore \] \[LHL=\underset{x\to {{0}^{-}}}{\mathop{\lim }}\,\frac{\sin x}{-x}=-1\] And \[RHL=\underset{x\to {{0}^{+}}}{\mathop{\lim }}\,\frac{|\sin x|}{x}=1\] Hence, limit does not exist.


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