JEE Main & Advanced JEE Main Paper (Held On 9 April 2016)

  • question_answer
    If \[2\int\limits_{0}^{1}{{{\tan }^{-1}}xdx}=\int\limits_{0}^{1}{{{\cot }^{-1}}}(1-x+{{x}^{2}})dx\]then\[\int\limits_{0}^{1}{{{\tan }^{-1}}}(1-x+{{x}^{2}})dx\]is equal to:   JEE Main Online Paper (Held On 09 April 2016)

    A) \[\log 2\]

    B) \[\frac{\pi }{2}+\log 2\]

    C) \[\log 4\]                            

    D) \[\frac{\pi }{2}-\log 4\]

    Correct Answer: A

    Solution :

                    \[2\int\limits_{0}^{1}{{{\tan }^{-1}}}xdx=\int\limits_{0}^{1}{{{\cot }^{-1}}}(1-x+{{x}^{2}})dx\]     ?(1) \[\int\limits_{0}^{1}{{{\tan }^{-1}}}(1-x+{{x}^{2}})dx=\int\limits_{0}^{1}{\left\{ \frac{\pi }{2}-{{\cot }^{-1}}(1-x+{{x}^{2}})dx \right\}}\]\[=\frac{\pi x}{2}\left| _{0}^{1} \right.-2\int\limits_{{}}^{{}}{{{\tan }^{-1}}xdx=\frac{\pi }{2}-2\left( \frac{\pi }{4}-\frac{1}{2}\ell n2 \right)}=\ell n2\]                                


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