Evaluating Absolute Value Functions - Sharp EL9600C - Graphing Calculator Handbook

Evaluating Absolute Value Functions

The absolute value of a real number x is defined by the following:
|x| = x if x
-x if x
Note that the effect of taking the absolute value of a number is to strip away the minus sign
if the number is negative and to leave the number unchanged if it is nonnegative.
Thus, |x| 0 for all values of x.
Example
Evaluate various absolute value functions.
1.
Evaluate |- 2(5-1)|
2.
Is |-2+7| = |-2| + |7|?
Evaluate each side of the equation to check your answer.
Is |x + y| =|x|+ |y| for all real numbers x and y ?
If not, when will |x + y| = |x|+|y| ?
6-9
3. |6-9|
Is | | =
1+3 |1+3|
Evaluate each side of the equation to check your answer. Investigate with
more examples, and decide if you think |x / y|=|x|/|y|
Before
There may be differences in the results of calculations and graph plotting depending on the setting.
Start
Return all settings to the default value or to delete all data.
Step & Key Operation
(When using EL-9600)
*Use either pen touch or cursor to operate.
1
1
Access the home or computation
-
screen.
1
2
Enter y = |-2(5-1)| and evaluate.
-
-
B 1 (
MATH
* *
1 )
ENTER
2
1
-
Evaluate|-2 + 7|. Evaluate|-2|+|7|.
CL
-
( )
1
MATH
*
-
1 ( )
MATH
*
1 7
ENTER
*
0
0
?
(When using EL-9600)
) 2 ( 5 —
+
2 7
ENTER
+
2
MATH
EL-9600/9400 Graphing Calculator
Display
The solution is + 8.
|-2 + 7| = 5, |-2| + |7| = 9
|-2 + 7|
Notes
|-2| + |7|.
8-5