,
=, and 
from
the TEST menu are evaluated by the calculator as either 1 or 0 according
as the expression is true or false for a given value of x. Thus, (x>2)*(3x–1)
evaluates to 0*(3x–1)=0 when x£2
and to 1*(3x–1)= 3x–1 when x>2.General method: The trick to this is knowing that expressions involving,
<, >, £,,
=, and from
the TEST menu are evaluated by the calculator as either 1 or 0 according
as the expression is true or false for a given value of x. Thus, (x>2)*(3x–1)
evaluates to 0*(3x–1)=0 when x£2
and to 1*(3x–1)= 3x–1 when x>2.
Example: To graph the function,
insert the following formula as y1
y1= (x<1)(x+1)+(x=1)(3)+(x>1)(1–x)
Notes:The inequality and equality symbols are found in the TEST menu.
Isolated points such as (1, 3) in the above example will not be visible unless you insure that the x-coordinate of that point is used by the calculator as a plotted point. Usually, this can be handled from the GRAPH/ZOOM menu by selecting ZDECM.
Also, if the "connected" option is turned on for this type of graphing, you will get false information at discontinuities. To turn this off, choose dotted style for this formula in the Y= menu. The plotting style is indicated to the extreme left of each formula. To change it, place the entry cursor over the formula and press STYLE (found above F3 by pressing MORE when viewing the second line under y(x)=.) Repeatedly pressing STYLE will cause the indicator to cycle through the possible styles. Choose the three distinct dots for dotted style.
| Here is what the above function should look like if graphed as described above. | ||||
 |
