Monotonicity of the Riemann integral (source code)

= Monotonicity of the Riemann integral

If Riemann-integrable functions satisfy $f(x)\leq g(x)$ throughout $[a,b]$, then
$$
\int_a^bf(x)\,dx\leq\int_a^bg(x)\,dx.
$$
This follows directly by comparing their lower and upper Darboux sums, or their Riemann sums on a common sequence of refining partitions.