11-14   Applications
Examine the inequality 
.
4X
òì
3X+5<
.
2X+4 graphically. Use the TEST functions to
explore the values of X where the inequality is true and where it is false.
1. Press 
3
. Select 
DOT
, 
SIMUL
, and the default mode
settings. Press 
2
 
"
, and turn off all stat plots.
2. Press 
(
, and turn off all functions. Enter the left side of
the inequality as 
Y1
, the right side as 
Y2
, and the statement
of the inequality as 
Y3
. 
Y3
 evaluates to 1 if true and 0 if
false.
3. Press 
)
, and enter these Window variable values.
Xmin=
ë
10 Ymin=
ë
10
Xmax=10 Ymax=10
Xscl=5 Yscl=5
4. Press 
+
. Press 
8
 
8
 to move to 
Y3
. Trace the
inequality, observing the value of X. 
Y3
 is 1 when 
Y1 
< 
Y2
,
and 
Y3
 is 0 when 
Y1
 ≥ 
Y2
.
5. Press 
(
 and turn off 
Y1 
and
 Y2
. Enter equations to graph
only the inequality.
6. Press 
+
. Notice that the values of 
Y3
 and 
Y4
 are zero
where the inequality is false.
Graphing Inequalities
Procedure