CEE Kerala Engineering CEE Kerala Engineering Solved Paper-2000

  • question_answer
    \[\underset{x\to 3}{\mathop{\lim }}\,\frac{{{x}^{2}}-9}{|x-3|}\]:

    A)  0                                            

    B)  3                            

    C)  \[\infty \]                          

    D)         6

    E)  does not exist

    Correct Answer: E

    Solution :

    \[\underset{x\to 3}{\mathop{\lim }}\,\frac{({{x}^{2}}-9)}{|x-3|}\] Now,     \[|x-3|=\left\{ \begin{matrix}    x-3, & if\,x>3  \\    -(x-3), & if\,x<3  \\ \end{matrix} \right.\] \[\underset{x\to {{3}^{+}}}{\mathop{\lim }}\,\frac{{{x}^{2}}-9}{|x-3|}=\underset{x\to {{3}^{+}}}{\mathop{\lim }}\,\frac{(x+3)(x-3)}{(x-3)}=6\] and\[\underset{x\to {{3}^{-}}}{\mathop{\lim }}\,\frac{{{x}^{2}}-9}{|x-3|}=\underset{x\to {{3}^{-}}}{\mathop{\lim }}\,\frac{(x+3)(x-3)}{-(x-3)}=-6\] \[\therefore \]  Limit does not exist.


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