複選題
5. Which of the following statement is TRUE? (A)
xf(x)dx =
f(x)dx when f is continuous on [a, b]. (B)
when f is continuous on [a, b] and f(x) ≥ 0 for all x ∈ [a, b]. (C) If f and g are differentiable and 0<f(x) ≤ g(x) on [a, b] then f'(x) ≤ g(x). (D) If f and g are continuous and 0< f(x) ≤ g(x) on [a, b] then
f(x)dx≤
g(x)dx.