Question 39
DifferentiationIf y = cos 3x, find dy/dx.
- A.−3sin 3x
- B.⅓sin 3x
- C.−⅓sin 3x
- D.3sin 3x
Show the answer and explanation
Answer: A (−3sin 3x)
Explanation
The derivative of cos u is −sin u × du/dx. Here u = 3x, so dy/dx = −3 sin 3x.
If y = cos 3x, find dy/dx.
Answer: A (−3sin 3x)
The derivative of cos u is −sin u × du/dx. Here u = 3x, so dy/dx = −3 sin 3x.