Game Development Reference
In-Depth Information
Graphs of Inverses
When you work with inverse values, such as
1
x
, you create a graph that is
undefined at
x
= 0. The domain of such graphs consists of all real numbers
except 0. Zero is excluded because division by 0 is not defined. For this reason,
when you use Visual Formula to generate a graphical representation of inverse
values, you must use the Exclude option to prevent calculations that might
involve using 0 as the divisor.
Note
Visual Formula issues a warning if you set up an equation that allows you to divide by 0. To adjust
for this situation, use the Exclude option to restrict the range of values you allow for the
calculation.
To employ Visual Formula to implement an equation that generates values
that are the inverses of the domain values, use the following steps (refer to
Figure 10.21):
1. Click the menu item for Value. Then click in the equation composition area
to position a Value field. Type a 1 in the Value field.
2. Click the Divide menu item. Then click to the right of the Value field to
position the division sign.
3. Again, click on the Value menu item. Place a Value field immediately after
the division sign. Type an x in the Value field.
4. Now proceed to the lower-right panel and find the Exclude controls. As
mentioned previously, you must exclude 0 from the values that are used in
the calculations of the inverse of the domain values. To exclude 0, designate
the range of values to exclude. To exclude a range that includes only
0.1 to
0.1, manually type
0.3 in the From field or use the control arrows. Then
manually type 0.1 in the To field or use the control arrows.
5. Verify that the Exclude option is checked. If it is not checked, check it.
6. In the Chart panel, set the Zoom values to
3 and the Width values to 3. Set
the Points value to 8.
7. Click the Chart for Formula 1 button to generate the graph. Figure 10.21
illustrates the graph of inverse values that results.
