11th Class Mathematics Sample Paper Mathematics Olympiad - Sample Paper-7

  • question_answer
    If \[\mathbf{y}=\frac{x}{1+\tan x}\]then \[\frac{dy}{dx}\] is equal to;

    A)  \[\frac{1+\tan x-x.{{\sec }^{2}}x}{{{(1+\tan x)}^{2}}}\]

    B)  \[\frac{1+\tan x+x.{{\sec }^{2}}x}{{{(1+\tan x)}^{2}}}\]

    C)  \[\frac{1-\tan x-x.{{\sec }^{2}}x}{{{(1+\tan x)}^{2}}}\]

    D)  None of these

    Correct Answer: A

    Solution :

    [a] \[\because y=\frac{x}{(1+\tan x)}\] \[\therefore \frac{dy}{dx}=\frac{(1+\tan x).1-x(0+{{\sec }^{2}}x)}{{{(1+\tan x)}^{2}}}\] \[=\frac{1+tanx-x.se{{c}^{2}}x}{{{\left( 1+tanx \right)}^{2}}}\]


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