JEE Main & Advanced Sample Paper JEE Main Sample Paper-11

  • question_answer
    \[\underset{x\to 0}{\mathop{\lim }}\,\frac{\tan x\sqrt{\tan x}-\sin x\sqrt{\sin x}}{{{x}^{3}}.\sqrt{x}}\] equals

    A)  1/4                       

    B)  3/4

    C)  1/2                                       

    D)  1

    Correct Answer: B

    Solution :

     \[\underset{x\to 0}{\mathop{\lim }}\,\frac{{{(\tan x)}^{3/2}}[1-{{(\cos x)}^{3/2}}]}{{{x}^{3/2}}.{{x}^{2}}}\] \[=1\times \underset{x\to 0}{\mathop{\lim }}\,\frac{1-{{\cos }^{3}}x}{{{x}^{2}}}.\frac{1}{1+{{(\cos x)}^{3/2}}}\] \[=\frac{1}{2}.\frac{1}{2}(1+\cos x+{{\cos }^{2}}x)=\frac{3}{4}\]


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