Delta integral of nonnegative function
From timescalewiki
Theorem
If $f(t) \geq 0$ for all $a \leq t < b$ then $$\displaystyle\int_a^b f(t) \Delta t \geq 0,$$ where $\int$ denotes the delta integral.
If $f(t) \geq 0$ for all $a \leq t < b$ then $$\displaystyle\int_a^b f(t) \Delta t \geq 0,$$ where $\int$ denotes the delta integral.