Differentiation Question 5

Question: Differential coefficient of $ \sqrt{\sec \sqrt{x}} $ is

[MP PET 1996]

Options:

A) $ \frac{1}{4\sqrt{x}}{{(\sec \sqrt{x})}^{3/2}}\sin \sqrt{x} $

B) $ \frac{1}{4\sqrt{x}}\sec \sqrt{x}\sin \sqrt{x} $

C) $ \frac{1}{2}\sqrt{x}{{(\sec \sqrt{x})}^{3/2}}\sin \sqrt{x} $

D) $ \frac{1}{2}\sqrt{x}\sec \sqrt{x}\sin \sqrt{x} $

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Answer:

Correct Answer: A

Solution:

$ \frac{d}{dx}( \sqrt{\sec \sqrt{x}} )=\frac{1}{2\sqrt{\sec \sqrt{x}}}.\frac{d}{dx}(\sec \sqrt{x}) $

$ =\frac{1}{2{{(\sec \sqrt{x})}^{1/2}}}.\sec \sqrt{x}.\tan \sqrt{x}.\frac{1}{2\sqrt{x}} $

$ x^{2}=\cos 2\theta $ .