- Enter the function
*f*(*x*) in the text input field marked "*f*(*x*)=" (Example:*f*(*x*)=4-*x*^{2}) - Click the "Graph" button (this button also refreshes the graph)
- Enter the endpoints of the interval [
*a*,*b*] for the definite integral in the text input fields marked "*a*=" and "*b*=", and click the "Graph" button to refresh (Example: [*a*,*b*]=[-2,2]) - Use the "+" and "-"
buttons under the label marked "
*n*=" to change the number of subintervals used for the approximation (Example:*n*=8) - The slider determines which point in each subinterval is used to determine the height of the rectangle, from left endpoint to right endpoint (Example: left endpoint)
- The "Left", "Mid", and "Right" buttons specify left endpoint, midpoint, and right endpoint, respectively, and adjust the slider appropriately
- To erase the graph and all input fields, setting the
slider to a default position and
*n*to a default value, click the "Clear" button

Polynomial:f (x)=4-x^{2}[ a,b]=[-2,2]n=20 for both left|mid|right |
Exponential:f (x)=e^{2}[ a,b]=[0,2]n=10 for both left|mid|right |
Trigonometric:f (x) = sin x[ a,b]=[0,3.14159]n=6 for bothleft|mid|right |

The graph of