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

  • question_answer
    The value of the definite integral, \[\int\limits_{{{\theta }_{1}}}^{{{\theta }_{2}}}{\frac{d\theta }{1+\tan \theta }}=\frac{501\pi }{K}\]where \[{{\theta }_{2}}\frac{1003\pi }{2008}\]and \[{{\theta }_{1}}=\frac{\pi }{2008}.\]The value of K equals

    A)  2007                     

    B)  2006

    C)  2009                     

    D)  2008

    Correct Answer: D

    Solution :

     \[{{\theta }_{1}}+{{\theta }_{2}}=\frac{\pi }{2}\] \[\therefore \]\[\int\limits_{{{\theta }_{1}}}^{{{\theta }_{2}}}{\frac{d\theta }{1+\tan \left( \frac{\pi }{2}-\theta  \right)}}\int\limits_{{{\theta }_{1}}}^{{{\theta }_{2}}}{\frac{\tan \theta d\theta }{1+\tan }}\]and also\[\int\limits_{\theta 2}^{\theta 2}{\frac{d\theta }{1+\tan \theta }}\] \[\therefore \]\[2I=\int\limits_{\theta 2}^{\theta 2}{d\theta ={{\theta }_{2}}-{{\theta }_{1}}}=\frac{1002\pi }{2008}\Rightarrow I=\frac{501\pi }{2008}\] Hence, \[K=2008\]


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