Evaluate the following sum on the TI-85 or TI-86 calculator:

We will need to use two commands which can be found on the MATH/MISC menu:

The following diagram shows the relationship between the entries of the seq command and the summation symbol:

[Press here to see animation]

The last 1 in the command indicates the step size. [We use a step size of 1 to indicate that x increases by 1 in each step.]

The result of this command is a list:

Press here to see how the terms of this list refer to our summation. Unfortunately, this list is too long to appear on the screen on the calculator. Use the right and left arrow keys on the calculator to view the list.

The sum command adds up the elements of a list.

Putting these together, we get

[Press here to see animation]

There is no need to use these commands separately; we can combine them as in the following:

Press here to see another example.