Riemann Sums

Graphs a function f(x) and approximations to the area under the graph of f(x) for a given interval, using sums of areas of rectangles with the heights of the rectangles determined by f(x).
How to use   ||   Examples   ||   Other Notes

How to use
The text input field for f (x) can accept a wide variety of expressions to represent functions, and the buttons under the graph allow various manipulations of the graph coordinates. The text input fields for a and b can accept real numbers in decimal notation.
f (x)=4-x2
n=20 for both   
f (x)=e2
n=10 for both   
f (x) = sin x
n=6 for both

Other Notes
The graph of f (x) is shown, with the rectangles over subintervals of [a,b] drawn in outline so that positive areas are green and negative areas are red. The approximate area computed is shown in the label marked "Area=".