This program calculates a Riemann Sum for a function with two independent
variables, taking the form Z = F(x,y); that is to say, it calculates the sum
, approximating the integral
. It is noteworthy in that it allows the use
of expressions in the limits of the inner integral, allowing integration of nonrectangular
regions; however, it is necessary to specify the order of integration. Values for
each rectangular subdivision are calculated at the center of the subdivision.
Note: This program uses the calculator's 'Y0', 'Y9', and 'Y8' graphing
functions in it's calculations, and will overwrite any equations previously stored
there.
