Sharp EL-9900 - Manual (Page 66)

13
Advanced Keyboard/ALGEBRA USING THE SHARP EL-9900
Copyright © 2002, Sharp Electronics Corporation. Permission is granted to photocopy for educational use only.
1. The inequality -1
≤ 2x – 5 ≤ 7 is commonly referred to as a “double” inequality.
2. Clear any previously entered functions by pressing Y= CL .
3. Enter Y1 = -1, Y2 = 2X – 5, and Y3 = 7.
4. Press ZOOM A (ZOOM) 5 (Default) to view the line y = 2x – 5 between
the lines y = -1 and y = 7.
5. Press 2ndF CALC 2 (Intsct) to find the point of intersection of the lines
y = 2x – 5 and y = -1 at (2, -1). Press
▲ to move the tracer to the y = 7 line.
Press 2ndF CALC 2 (Intsct) to find y = 2x – 5 and y = 7 at (6, 7).
6. The solution to the “double” inequality -1
≤ 2x – 5 ≤ 7 consists of all values of
x in between, and including, 2 and 6 (i.e., x
≥ 2 and x ≤ 6). The solution is
2
≤ x ≤ 6.
DOUBLE INEQUALITIES