Sharp EL9900 manual Continuing key operations omitted

EL-9900 Graphing Calculator

Step & Key Operation Display Notes

2-2Use the cursor to check the position of each point. (Zoom in as necessary).

GRAPH or or or

2-3Substitute points and confirm whether they are in the solution region.

-	1 •	6	+
( )

2 X 1•8 ...

(Continuing key operations omitted.)

Points in the solution region are (2.8, -1.4) and (-8, 4). Points outside the solution region are (-1.6, 1.8) and (-2, -5).

.(-1.6, 1.8): -1.6 + 2 ✕ 1.8 = 2

. ➞This does not materialize. (-2, -5): -2 + 2 ✕ (-5) = -12

(-2)2+ (-5) = -1

. ➞This does not materialize. (2.8, -1.4): 2.8 + 2 ✕ (-1.4) = 0 (2.8)2 + (-1.4) = 6.44

. ➞This materializes. (-8, 4): -8 + 2 ✕ 4 = 0

(-8)2+ 4 = 68

➞This materializes.

Graphical solution methods not only offer instructive visualization of the solution process, but they can be applied to inequalities that are often very difficult to solve algebraically. The EL-9900 allows the solution region to be indicated visually using the Shading feature. Also, the free-moving tracer or Zoom-in feature will allow the details to be checked visually.

9-4