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

  • question_answer
    \[\int_{{}}^{{}}{\frac{1+{{x}^{2}}}{\sqrt{1-{{x}^{2}}}}dx=}\]    [IIT 1977]

    A)            \[\frac{3}{2}{{\sin }^{-1}}x-\frac{1}{2}x\sqrt{1-{{x}^{2}}}+c\]

    B)            \[\frac{3}{2}{{\sin }^{-1}}x+\frac{1}{2}x\sqrt{1-{{x}^{2}}}+c\]

    C)            \[\frac{3}{2}{{\cos }^{-1}}x-\frac{1}{2}x\sqrt{1-{{x}^{2}}}+c\]

    D)            \[\frac{3}{2}{{\cos }^{-1}}x+\frac{1}{2}x\sqrt{1-{{x}^{2}}}+c\]

    Correct Answer: A

    Solution :

                       Put \[x=\sin \theta \Rightarrow dx=\cos \theta \,d\theta ,\] then it reduces to \[\int_{{}}^{{}}{(1+{{\sin }^{2}}\theta )\,d\theta }=\theta +\frac{1}{2}\int_{{}}^{{}}{(1-\cos 2\theta )\,d\theta }\]            \[=\frac{3\theta }{2}-\frac{1}{2}\sin \theta \sqrt{1-{{\sin }^{2}}\theta }+c=\frac{3}{2}{{\sin }^{-1}}x-\frac{1}{2}x\sqrt{1-{{x}^{2}}}+c\].


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