Sharp EL9900 manual Math

EL-9900 Graphing Calculator

Step & Key Operation Display Notes

2-2Is x + y = x +y? Think about this problem according to the cases

when x or y are positive or negative.

If x ≥ 0 and y ≥ 0 [e.g.; (x, y) = (2,7)]

If x ≤ 0 and y ≥ 0 [e.g.; (x, y) = (-2, 7)]

If x ≥ 0 and y ≤ 0 [e.g.; (x, y) = (2, -7)]

If x ≤ 0 and y ≤ 0 [e.g.; (x, y) = (-2, -7)]

3-1	Evaluate				6-9				. Evaluate					6-9			.
					1+3								1+3
		CL		MATH		1			a/b	6		—				9
			1		+		3			ENTER
		MATH	1		6			—		9					a/b
		MATH	1		1		+			3	ENTER
3-2	Is x /y = x/y?
	Think about this problem according
	to the cases when x or y are positive
	or negative.

If x ≥ 0 and y ≥ 0 [e.g.; (x, y) = (2,7)]

If x ≤ 0 and y ≥ 0 [e.g.; (x, y) = (-2, 7)]

If x ≥ 0 and y ≤ 0 [e.g.; (x, y) = (2, -7)]

If x ≤ 0 and y ≤ 0 [e.g.; (x, y) = (-2, -7)]

x +y = 2 + 7 = 9

x+y = 2 + 7 = 9

x + y = x + y.

x +y = -2 + 7 = 5

x+y = -2 + 7 = 9

x + y ≠ x + y.

x +y = 2-7 = 5

x+y = 2 + -7 = 9

x + y ≠ x + y.

x +y = -2-7 = 9

x+y = -2 + -7 = 9

x + y = x + y.

Therefore x +y=x+ywhen x ≥					0 and y ≥ 0,
and when x ≤ 0 and y ≤ 0.
	6-9		= 0.75 ,		6-9	= 0 .75
		1+3
				1+3

➞6-9 = 6-9

1+3 1+3

x /y = 2/7 = 2/7

x/y = 2 /7 = 2/7

x /y = x / y

x /y = (-2)/7 = 2/7

x/y = -2 /7 = 2/7

x /y = x / y

x /y = 2/(-7) = 2/7

x/y = 2 /-7 = 2/7

x /y = x / y

x /y = (-2)/-7 = 2/7

x/y = -2 /-7 = 2/7

x /y = x / y

The statement is true for all y ≠ 0.

The EL-9900 shows absolute values with , just as written on paper, by using the Equation editor. The nature of arithmetic of the absolute value can be learned through arithmetical operations of absolute value functions.

10-4