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

  • question_answer
    \[\int_{{}}^{{}}{\frac{{{\sec }^{2}}x}{1+\tan x}\ dx=}\]    [MP PET 1987]

    A)            \[\log (\cos x+\sin x)+c\]

    B)            \[\log ({{\sec }^{2}}x)+c\]

    C)            \[\log (1+\tan x)+c\]

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

    Correct Answer: C

    Solution :

                       Put \[t=1+\tan x\Rightarrow dt={{\sec }^{2}}x\,dx\]            \[\int_{{}}^{{}}{\frac{{{\sec }^{2}}x}{1+\tan x}}\,dx=\int_{{}}^{{}}{\frac{1}{t}\,dt=\log t+c}\]\[=\log (1+\tan x)+c.\]


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