Sharp EL9900 manual Evaluating Absolute Value Functions, +3 1+3

EL-9900 Graphing Calculator

Evaluating Absolute Value Functions

The absolute value of a real number x is defined by the following:

x =	x if	x ≥	0
	-xif	x ≤	0

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 ?

3. Is 6-9 = 6-9?

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.
Starting		Return all settings to the default value and delete all data.
	Step & Key Operation		Display	Notes

1-1Access the home or computation screen.

1-2Enter y = -2(5-1)and evaluate.

The solution is +8.

MATH B

1 )

1	( )	2	(	5	—
	-

ENTER

2-1Evaluate-2 + 7. Evaluate-2+7.													-2 + 7 = 5, -2 + 7 = 9
													➞ -2 + 7 ≠ -2 + 7.
	CL
	MATH	1		(	-	)	2	+	7		ENTER
	MATH	1		(		)	2			+		MATH
				-
1		7
			ENTER

10-4