Sharp EL9900 manual EL-9900 Graphing Calculator

		EL-9900 Graphing Calculator
Step & Key Operation	Display	Notes
2-1Enter y = 3(4 - 2x) for Y1 and
y = 5 - x for Y2.

Y= (7 times) DEL

ENTER 5 — X//T/n

(4 times)

2-2View the graph.

GRAPH

2-3Access the Set Shade screen.

2nd F DRAW G

1

2-4

2-5

2-6

Set up the shading.

2nd—F VARS A ENTER A 2

2nd F VARS ENTER 1

View the shaded region.

GRAPH

Find where the graphs intersect and solve the inequality.

2nd F CALC 2

Since the inequality being solved is Y1 ≥ Y2, the solu- tion is where the graph of Y1 is “on the top” and Y2 is “on the bottom.”

The point of intersection is (1.4, 3.6). Since the shaded region is to the left of x = 1.4, the solution to the inequality 3(4 - 2x) ≥ 5 - x is all values of x such that x ≤ 1.4.

Graphical solution methods not only offer instructive visualization of the solution process, but they can be applied to inequalities that are often difficult to solve algebraically. The EL-9900 allows the solution region to be indicated visually using the Shade feature. Also, the points of intersection can be obtained easily.

9-1