Differentiation Question 227

Question: If $ y=\sin ( \frac{1+x^{2}}{1-x^{2}} ) $ , then $ \frac{dy}{dx}= $

[AISSE 1987]

Options:

A) $ \frac{4x}{1-x^{2}}.\cos ( \frac{1+x^{2}}{1-x^{2}} ) $

B) $ \frac{x}{{{(1-x^{2})}^{2}}}.\cos ( \frac{1+x^{2}}{1-x^{2}} ) $

C) $ \frac{x}{(1-x^{2})}.\cos ( \frac{1+x^{2}}{1-x^{2}} ) $

D) $ \frac{4x}{{{(1-x^{2})}^{2}}}.\cos ( \frac{1+x^{2}}{1-x^{2}} ) $

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Answer:

Correct Answer: D

Solution:

$ \frac{dy}{dx}=\cos ( \frac{1+x^{2}}{1-x^{2}} )[ \frac{(1-x^{2})2x+(1+x^{2})2x}{{{(1-x^{2})}^{2}}} ] $

$ =\frac{4x}{{{(1-x^{2})}^{2}}}\cos ( \frac{1+x^{2}}{1-x^{2}} ) $ .