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MATHEMATICS

JAMB 2009 - Question 36

Mathematics 2009 JAMB Past Questions - Question 36: If y=3 cos 4x, dy/dx equals

If y=3 cos 4x, dy/dx equals

A: 6 sin 8x

B: -24 sin 4x

C: 12 sin 4x

D: -12 sin 4x

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Correct Answer

Explanation

if y = 3 cos 4x; dy/dx equalsdy=3(4-sin4x) dx = -12sin 4xTo find dy/dx, we need to differentiate y = 3cos(4x) with respect to x.Using the chain rule, we differentiate cos(4x) with respect to 4x and multiply it by the derivative of 4x with respect to x.The derivative of cos(4x) with respect to 4x is -sin(4x), and the derivative of 4x with respect to x is 4.Therefore, dy/dx = 3 * (-sin(4x)) * 4 = -12sin(4x).Hence, the value of dy/dx is -12sin(4x).