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GUJCET · Maths · Application of Derivatives
Which of the following function is decreasing in \(\left(0, \frac{\pi}{8}\right)\)?
- A \(\tan 4 x\)
- B \(\sin x\)
- C \(\cos 4 x\)
- D \(-\cos x\)
Answer & Solution
Correct Answer
(C) \(\cos 4 x\)
Step-by-step Solution
Detailed explanation
Let \(f(x) = \cos 4x\). \(f'(x) = \frac{d}{dx}(\cos 4x) = -4 \sin 4x\)
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