If f is continuous and [0 to 8] f(x)dx = 15, evaluate [0 to 2] f(4x)dx

Question

If f is continuous and [0 to 8] f(x)dx = 15, evaluate [0 to 2] f(4x)dx

Answer 1

Let u=4x and du=4dx dx=du/4 so the integral ∫₀²f(4x)dx becomes ∫₀⁸f(u)du/4 = 15/4