Question

Find the derivative of cos(3x-5)²

Answer 1

We know that,
Derivative of cos x² = -sin x . d/dx(x²)
                               = -sin x . 2x
                               = -2 x sin x
Now given question is cos(3x-5)²  
cos(3x-5)² = -sin (3x-5)² . d/dx (3x-5)²
cos(3x-5)² = -sin (3x-5)² . 2 (3x-5) . d/dx (3x-5)
cos(3x-5)² = -sin (3x-5)² . 2 (3x-5) . 3
cos(3x-5)² = -6 (3x-5) sin (3x-5)²
cos(3x-5)² = (-18x + 30) . sin (3x-5)²
cos(3x-5)² = (30 - 18x) . sin (3x-5)²
This is the required answer. Hope it will help you. Thanks