Sharp EL-9900 - Manual (Page 67)

14
Advanced Keyboard/ALGEBRA USING THE SHARP EL-9900
Copyright © 2002, Sharp Electronics Corporation. Permission is granted to photocopy for educational use only.
1. The solution region of a system of inequalities consists of all points (a, b)
such that when x = a and y = b, all inequalities in the system are true.
2. For example, to graph the solution region for the system
2x + y
≥ 1
x 2 + y
≤ 1,
first rewrite each inequality in the system so that the left-hand-side is y:
y
≥ 1 – 2x
y
≤ 1 – x 2
3. Press Y= CL and enter 1 – 2X in Y1 and 1 – X 2 in Y2.
4. Next, shade the points that have a y-value less than Y2 and greater than Y1.
Do this by pressing 2ndF DRAW G (SHADE) 1 (Set) 2ndF VARS A
ENTER 1 2ndF VARS ENTER 2 .
5. Graph the system by pressing ZOOM A (ZOOM) 7 (Dec).
6. Turn off the shading by pressing 2ndF DRAW G (SHADE) 2 (INITIAL).
SYSTEMS OF INEQUALITIES
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