Suppose you would like to find the area under the parabola

from 2 to some point x. 

Since this area is a function x (it depends on the value of x we choose on the x-axis) we could call this F(x) or

You can type this integral as a function in one of the function slots. 

In this example we are looking for a function that represents the graph of the area under the function from 2 to an x value in the window of the calculator.  Note you should write the function as

picture.

How did it get this graph?  Let's analyze the graph in stages.  When you first hit GRAPH the calculator will first try to find

As long as the calculator is calculating area to the left of 2, the area will be negative.  The area will be zero when the calculator is determining

When the calculator is finding the area from 2 to any point to the right of 2 the area will be positive and increasing. 

So the final graph is

What would happen if you asked it to graph