For a given bounded function 
over a partition of a given interval, the upper sum is the sum of box areas 
using the supremum 
of the function 
in each subinterval ![[x_(k-1),x_k]](/images/equations/UpperSum/Inline5.svg)
.
Upper Sum
See also
Lower Sum, Riemann Integral, Upper IntegralExplore with Wolfram|Alpha
Cite this as:
Weisstein, Eric W. "Upper Sum." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/UpperSum.html