Take a look at the applet: ??
Here you see the graph of a function where takes values from to .
If you let increase with a set step length
, then you can draw up a table of the corresponding increments of the function value.
If your step length then the table will look like this:
-2 | -1 | 0 | 1 | 2 | 3 | 4 | |
26 | 42 | 46 | 44 | 42 | 46 | 64 | |
|
16 | 4 | -2 | -2 | 4 | 16 |
The corresponding diagram of increments is shown within the same graph.
The increment of the function is the difference between the function value at and that at the previous step, .
This is useful if you know the formula.
You can then use your graphing calculator and enter at Y1= the original formula for
the function ant at Y2:
Y2=Y1(X)-Y1(X-1).
This will give you the table of increments at Y2.
The calculator, however, cannot make a diagram of increments such as you see in the
graph above.