show that if "f" is integrable then f(x) is less then or equal to 0 on [a,b] is equal to the integral from a to b of f(x) dx is greater then or equal to 0
show that if "f" is integrable then f(x) is less then or equal to 0 on [a,b] is equal to the integral from a to b of f(x) dx is greater then or equal to 0
Please try to ask the question more clearly, that is incomprehensible.
show that if "f" is integrable then f(x) is less then or equal to 0 on [a,b] is equal to the integral from a to b of f(x) dx is greater then or equal to 0
Since $\displaystyle f(x)=-1$ fits the conditions and assume $\displaystyle b>a$, then $\displaystyle \int_a^b (-1) dx=(a-b)<0$ this cannot be true in general.