JEE Main & Advanced Mathematics Functions Question Bank Continuity

  • question_answer
    If\[f(x)=|x-2|\], then [Roorkee 1984]

    A)            \[\underset{x\to 2+}{\mathop{\lim }}\,f(x)\ne 0\]                     

    B)            \[\underset{x\to 2-}{\mathop{\lim }}\,f(x)\ne 0\]

    C)            \[\underset{x\to 2+}{\mathop{\lim }}\,f(x)\ne \underset{x\to 2-}{\mathop{\lim }}\,f(x)\]   

    D)            \[f(x)\]is continuous at \[x=2\]

    Correct Answer: D

    Solution :

               Here \[f(2)=0\]                    \[\underset{x\to 2-}{\mathop{\lim }}\,f(x)=\underset{h\to 0}{\mathop{\lim }}\,\,f(2-h)=\underset{h\to 0}{\mathop{\lim }}\,\,\,|\,\,2-h-2\,\,|=0\]                    \[\underset{x\to 2-}{\mathop{\lim }}\,f(x)=\underset{h\to 0}{\mathop{\lim }}\,\,f(2-h)=\underset{h\to 0}{\mathop{\lim }}\,\,\,|\,\,2-h-2\,\,|=0\]                    Hence it is continuous at \[x=2\].


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