Riemann Sum Calculator

This program graphs the inputted function and number of rectangular approximators over the specified interval and calculates the estimated area with a right, left or midpoint Riemann sum.

Supports the following functions:
sin
cos
tan
arcsin
arccos
arctan
ln
log (base ten)

and the following constants:
e
pi (Note: type out "pi" in the function field to use)

Mimics TI-89 syntax
Coefficients and parenthesis may be used to denote multiplication, but ‘coefficient multiplication’ will not work with constants. This includes pi, which is denoted by “pi” rather than the symbol.
Examples:
o 6x is ok
o pi x is NOT ok; use pi*x
o (2 - x)sin(x) is ok
o sin(x)^2 is ok
o sin(x)^-1 will be 1/sin(x); use arcsin(x) for the inverse of sin(x)

Logarithms with bases other than e and 10 are not supported must be inputted via change of base.
Like any calculator, extreme functions and sets of values may generate unusual graphs.

Written in Python.