Differentiation Question 53

Question: Differential coefficient of $ {{\cos }^{-1}}(\sqrt{x}) $ with respect to $ \sqrt{(1-x)} $ is

[MP PET 1997]

Options:

A) $ \sqrt{x} $

B) $ -\sqrt{x} $

C) $ \frac{1}{\sqrt{x}} $

D) $ -\frac{1}{\sqrt{x}} $

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Answer:

Correct Answer: C

Solution:

Let $ y={{\cos }^{-1}}\sqrt{x} $ and $ z=\sqrt{1-x} $

$ \therefore \frac{dy}{dz}=\frac{\frac{-1}{\sqrt{1-x}}\times \frac{1}{2\sqrt{x}}}{-\frac{1}{2\sqrt{1-x}}}=\frac{1}{\sqrt{x}} $ .