How do you do this question?

Step-by-step explanation:

f(x) = 38 cos(x²)

Use chain rule to take the derivative.

f'(x) = -38 sin(x²) (2x)

f'(x) = -76x sin(x²)

Use product rule and chain rule to take the derivative.

f"(x) = -76x cos(x²) (2x) + (-76) sin(x²)

f"(x) = -152x² cos(x²) − 76 sin(x²)