JEE Main & Advanced Mathematics Differentiation Question Bank Derivative at a point Standard Differentiation

  • question_answer
    If \[y={{\tan }^{-1}}(\sec x-\tan x)\]then \[\frac{dy}{dx}=\] [Karnataka CET 2004]

    A)            2

    B)            ?2

    C)          ½

    D)            ?1/2

    Correct Answer: B

    Solution :

               \[y={{\tan }^{-1}}(\sec x-\tan x)\]                    \[\frac{dy}{dx}=\frac{1}{1+{{(\sec x-\tan x)}^{2}}}(\sec x\tan x-{{\sec }^{2}}x)\]                    \[\frac{dy}{dx}=\frac{{{\cos }^{2}}x.{{\sec }^{2}}x(\sin x-1)}{{{(1-\sin x)}^{2}}+{{\cos }^{2}}x}\]                    \[\frac{dy}{dx}=\frac{\sin x-1}{1-2\sin x+{{\sin }^{2}}x+{{\cos }^{2}}x}=\frac{\sin x-1}{2(1-\sin x)}=-\frac{1}{2}.\]


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