CEE Kerala Engineering CEE Kerala Engineering Solved Paper-2003

  • question_answer
    If\[f(x)=|x{{|}^{3}},\] then\[f(0)\] equals:

    A)  0                                            

    B)  1/2                       

    C)         \[-1\]                   

    D)         \[-1/2\]

    E)  none of these

    Correct Answer: A

    Solution :

    \[f(x)=|x{{|}^{3}}=\left\{ \begin{matrix}    0, & x=0  \\    {{x}^{3}}, & x>0  \\    -{{x}^{3}}, & x<0  \\ \end{matrix} \right.\] Now, \[Rf(0)=\underset{h\to 0}{\mathop{\lim }}\,\frac{f(h)-f(0)}{h}\] \[=\underset{h\to 0}{\mathop{\lim }}\,\frac{{{h}^{3}}-0}{h}=0\] and \[Lf(0)=\underset{h\to 0}{\mathop{\lim }}\,\frac{f(-h)-f(0)}{-h}\]                 \[=\underset{h\to 0}{\mathop{\lim }}\,\frac{-{{h}^{3}}-0}{-h}=0\] \[\because \]     \[Rf(0)=Lf(0)=0\] \[\therefore \]  \[f(0)=0\]


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