passwella.
Menu

JAMB Mathematics 1997 Question 39

Question 39

Differentiation

d/dx cos (3x2 − 2x) is equal to

  1. A.−sin (6x − 2)
  2. B.−sin (3x2 − 2x)
  3. C.(6x − 2)sin(3x2 − 2x)
  4. D.−(6x − 2)sin(3x2 − 2x)
Show the answer and explanation

Answer: D (−(6x − 2)sin(3x2 − 2x))

Explanation

By the chain rule, the derivative of cos u is −sin u × du/dx, with du/dx = 6x − 2.