JEE Main & Advanced Mathematics Indefinite Integrals Question Bank Integration by Parts

  • question_answer
    \[\int_{{}}^{{}}{\frac{{{\sin }^{-1}}x}{{{(1-{{x}^{2}})}^{3/2}}}\ dx=}\]     [AISSE 1983, 87]

    A)                 \[\frac{x}{\sqrt{1-{{x}^{2}}}}{{\sin }^{-1}}x+\frac{1}{2}\log (1-{{x}^{2}})+c\]

    B)                 \[\frac{x}{\sqrt{1-{{x}^{2}}}}{{\sin }^{-1}}x-\frac{1}{2}\log (1-{{x}^{2}})+c\]

    C)                 \[\frac{1}{\sqrt{1-{{x}^{2}}}}{{\sin }^{-1}}x-\frac{1}{2}\log (1-{{x}^{2}})+c\]

    D)                 \[\frac{1}{\sqrt{1-{{x}^{2}}}}{{\sin }^{-1}}x+\frac{1}{2}\log (1-{{x}^{2}})+c\]

    Correct Answer: A

    Solution :

                    Put \[t={{\sin }^{-1}}x\Rightarrow \sin t=x\Rightarrow \cos t\,dt=dx,\] then                 \[\int_{{}}^{{}}{\frac{{{\sin }^{-1}}x}{{{(1-{{x}^{2}})}^{3/2}}}\,dx}=\int_{{}}^{{}}{t{{\sec }^{2}}t\,dt=t\tan t+\log \cos t+c}\]                                 \[={{\sin }^{-1}}x\tan ({{\sin }^{-1}}x)+\log \cos ({{\sin }^{-1}}x)+c\]                                 \[=\frac{x}{\sqrt{1-{{x}^{2}}}}{{\sin }^{-1}}x+\frac{1}{2}\log (1-{{x}^{2}})+c.\]


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