engineering mathematics MCQ #786

If y = sin(2x) cos(x), then dy/dx = ?

engineering mathematics MCQ #786

  1. Question 1

    Q1. If y = sin(2x) cos(x), then dy/dx = ?

    • A) 2 cos(2x) cos(x) - sin(2x) sin(x)
    • B) 2 cos(2x) cos(x)
    • C) 2 sin(2x) sin(x)
    • D) cos(2x) sin(x)

    Answer: 2 cos(2x) cos(x) - sin(2x) sin(x)

    Explanation: Using the product rule, dy/dx = d(sin(2x) cos(x))/dx = sin(2x) d(cos(x))/dx + cos(x) d(sin(2x))/dx = sin(2x)(-sin(x)) + cos(x)(2cos(2x)) = 2 cos(2x) cos(x) - sin(2x) sin(x).