Applications Of Derivatives Question 151

Question: The angle between the curves $ y=\sin x $ and $ y=\cos x $ is

[EAMCET 2003]

Options:

A) $ {{\tan }^{-1}}(2\sqrt{2}) $

B) $ {{\tan }^{-1}}(3\sqrt{2}) $

C) $ {{\tan }^{-1}}(3\sqrt{3}) $

D) $ {{\tan }^{-1}}(5\sqrt{2}) $

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Answer:

Correct Answer: A

Solution:

If $ \sin x=\cos x\Rightarrow x=\pi /4 $

If $ y=\sin x\Rightarrow {{( \frac{dy}{dx} )} _{x=\pi /4}}=\frac{1}{\sqrt{2}} $

If $ y=\cos x\Rightarrow {{( \frac{dy}{dx} )} _{x=\pi /4}}=\frac{-1}{\sqrt{2}} $

$ \tan \theta =\frac{m_1-m_2}{1+m_1m_2}=2\sqrt{2}\Rightarrow ,\theta ={{\tan }^{-1}}(2\sqrt{2}) $ .