RAM Functions for TI-89

What are they?

These are a couple of functions I made really quickly before a test to do Rectangular Approximation Methods (RAMs). As far as I know they work perfectly, since I got an A on the test I used them on. =) Feel free to modify them and do whatever you want to them.

Descriptions of the functions:

lram = left ram
mram = midpoint ram
rram = right ram

All of the functions are used like this:
lram(starting position,ending position,number of subintervals)