Sharp EL-9900 Handbook Vol. 1 Operation Manual page 35

Step & Key Operation
2
2
Use the cursor to check the position
-
of each point. (Zoom in as necessary).
or
GRAPH
2
3
-
Substitute points and confirm
whether they are in the solution
region.
-
( ) 1
2 •
1
X
(Continuing key operations omitted.)
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.
or or
+
• 6
...
8
EL-9900 Graphing Calculator
Display
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
This does not materialize.
.
(-2, -5): -2 + 2
This does not materialize.
.
(2.8, -1.4): 2.8 + 2
This materializes.
.
(-8, 4):
This materializes.
Notes
1.8 = 2
(-5) = -12
(-2) 2 + (-5) = -1
(-1.4) = 0
2
(2.8) + (-1.4) = 6.44
-8 + 2 4 = 0
(-8) 2 + 4 = 68
9-4