JEE Main & Advanced Mathematics Differentiation Question Bank Self Evaluation Test - Limits and Derivatives

  • question_answer
    \[\underset{x\to 0}{\mathop{\lim }}\,\left[ \frac{\sin [x-3]}{[x-3]} \right],\] where \[[.]\] denotes greatest integer function is

    A) 0

    B) 1

    C) Does not exist

    D) sin 1

    Correct Answer: C

    Solution :

    [c] \[\underset{x\to 0}{\mathop{\lim }}\,\left[ \frac{\sin [x-3]}{[x-3]} \right]\] For \[x\to {{0}^{+}},[x-3]=-3\] \[\therefore \frac{\sin [x-3]}{[x-3]}=\frac{\sin (-3)}{-3}=\frac{\sin 3}{3}\in (0,1)\] \[\therefore \underset{x\to {{0}^{+}}}{\mathop{\lim }}\,\frac{\sin [x-3]}{[x-3]}=0\] For \[x\to {{0}^{-}},[x-3]=-4\] \[\therefore \frac{\sin [x-3]}{[x-3]}=\frac{\sin 4}{4}\] lies in (-1, 0) \[\therefore \underset{x\to {{0}^{-}}}{\mathop{\lim }}\,\left[ \frac{\sin [x-3]}{[x-3]} \right]=-1\] \[\therefore \] Limit does not exist.


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