Building Interactive Graphs In Desmos - Example with Riemann Sums

I show how we can use the free graphing calculator website Desmos.com to quickly build interactive graphs. As an example, I begin building a Riemann Sum demonstration from scratch. Then I move to a previously created demonstration (also with Riemann Sums) so show some of the additional features that you can build into your demonstration.
You can access the Riemann Sum demonstration used in the later portion of this video at: www.desmos.com/calculator/l4i...
Some features illustrated in the video:
* Creating variables, setting their parameters, and animating them.
* Using lists to easily work with a variable number of elements at once (such as the n rectangles in a Riemann sum). Lists are a POWERFUL feature of Desmos, because working with lists is essentially iterating over the list, effectively implementing something akin to a for-loop. They let you add graphical elements based on "indexing variables".
* Adding points to the graph and adding labels to display values of variables; also, enabling dragging of those points to modify those values. (This includes using backticks to display mathematics. The video does not highlight this, but it can be found in the linked graph.)
* Customizing the settings of a display, including font size and positioning.
* Restricting the domains of functions using "{ conditions }" expressions -- we restrict the domain of the constant functions which determine the heights of our rectangles.
* The use of the built-in functions max, min, and round as utilities to help easily customize our graphs and display.
* Using tables along with draggable points to add a "manipulative" element to the canvas, enabling users to modify variables like n and s (whether to sample at right or left endpoints) in a controlled way, without having to access the console.
* Support for summation notation as well as built-in calculation of definite integrals. (Desmos also supports derivatives, but this video does not touch on that.)
* Using folder and note objects to organize a graph and make it approachable to other users (and help you remember what you did!).

[@natep5765]

As a student watching this was incredibly helpful, thanks for taking the time to put this together!

[@DF-te2vm]

Fantastic

[@pavelslavchev2000]

Hi, the animation is really amazing, but I noticed that it does not draw the rectangle when n=1. Would anyone have a suggestion how to fix this =/. Thanks in advance for your help

[@JorgeGamaliel]

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