JEE Main & Advanced Mathematics Functions Question Bank Limits

  • question_answer
    \[\underset{x\to 0}{\mathop{\lim }}\,\frac{{{x}^{3}}\cot x}{1-\cos x}=\] [AI CBSE 1988; DSSE 1988]

    A)                 0

    B)                 1

    C)                 2

    D)                 ?2

    Correct Answer: C

    Solution :

                       \[\underset{x\to 0}{\mathop{\lim }}\,\,\,\frac{{{x}^{3}}\cot x}{1-\cos x}=\underset{x\to 0}{\mathop{\lim }}\,\,\left( \frac{{{x}^{3}}\cot x}{1-\cos x}\times \frac{1+\cos x}{1+\cos x} \right)\]                                                 \[=\underset{x\to 0}{\mathop{\lim }}\,\,{{\left( \frac{x}{\sin x} \right)}^{3}}\times \underset{x\to 0}{\mathop{\lim }}\,\,\cos x\times \underset{x\to 0}{\mathop{\lim }}\,\,(1+\cos x)=2\]


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