Filter
Top Products
EL-9900 Graphing Calculator
Solving Double Inequalities
The solution to a system of two inequalities in one variable consists of all values of the variable
that make each inequality in the system true. A system f (x)
≥
a, f (x)
≤
b, where the same expression
appears on both inequalities, is commonly referred to as a “double” inequality and is often written
in the form a
≤
f (x)
≤
b. Be certain that both inequality signs are pointing in the same direction and
that the double inequality is only used to indicate an expression in x “trapped” in between two
values. Also a must be less than or equal to b in the inequality a
≤
f (x)
≤
b or b
≥
f (x)
≥
a.
Solve a double inequality, using graphical techniques.
Example
2x - 5
≥
-1
2x -5
≤
7
1
Enter y = -1 for Y1, y = 2x - 5 for
Y2, and y = 7 for Y3.
The “double” inequality
given can also be written to
-1
≤
2x - 5
≤
7.
2
View the lines.
3
Find the point of intersection.
y = 2x - 5 and
y = -1 intersect at (2, -1).
9-2
Y=
(
-
)
1
25
7
2
2nd F CALC
—
ENTER
ENTER
GRAPH
NotesStep & Key Operation Display
There may be differences in the results of calculations and graph plotting depending on the setting.
Return all settings to the default value and delete all data.
Before
Starting
X/
/T/n