Suppose that a for all c [a, b] if and only if f(x) = 0 for all x [a, b]. (Compare with Exercise

Suppose that a

for all c ˆˆ [a, b] if and only if f(x) = 0 for all x ˆˆ [a, b]. (Compare with Exercise 5.1.4, and notice that f need not be nonnegative here.)

je f(x) dx =0