Differentiation Question 11

Question: If $ y={{(\sin x)}^{\tan x}} $ , then $ \frac{dy}{dx} $ is equal to

[IIT 1994; RPET 1996]

Options:

A) $ {{(\sin x)}^{\tan x}}.(1+{{\sec }^{2}}x.\log \sin x) $

B) $ \tan x.{{(\sin x)}^{\tan x-1}}.\cos x $

C) $ {{(\sin x)}^{\tan x}}.{{\sec }^{2}}x.\log \sin x $

D) $ \tan x.{{(\sin x)}^{\tan x-1}} $

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Answer:

Correct Answer: A

Solution:

Given $ y={{(\sin x)}^{\tan x}} $ ; $ \log y=\tan x.\log \sin x $

Differentiate with respect to x, $ \frac{1}{y}.\frac{dy}{dx}=\tan x.\cot x+\log \sin x.{{\sec }^{2}}x $

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