Basic Example of Evaluating a Riemann Sum

This is a very basic example showing the steps in evaluating a Riemann Sum as the estimate of an area under a curve over an interval.
Steps Include:
1) Partition the Interval. Determine width of subintervals.
2) Identify the "c" values in each subinterval.
3) Evaluate the heights of the boxes by evaluating function at each "c" value. Add them up and multiply by common width.
4) This is the ESTIMATE of the area under the curve over that interval.