Graphing Polynomials And Jumping To Find The Roots - Sharp EL-9900 Handbook Vol. 1 Operation Manual

Graphing Polynomials and Jumping to Find the Roots

A polynomial y = f (x) is an expression of the sums of several terms that contain different
powers of the same originals. The roots are found at the intersection of the x- axis and the
graph, i. e. when y = 0.
Example
Draw a graph of a polynomial and find the roots by using the Calculate feature.
1.
Graph the polynomial y = x
2.
Find the four roots one by one.
Before
There may be differences in the results of calculations and graph plotting depending on the setting.
Starting
Return all settings to the default value and delete all data.
Setting the zoom factors to 5 :
Step & Key Operation
1
1
- Enter the polynomial
4 3 - 5x 2
y = x + x
n
b 4
Y= X/ /T/ a
—
a b 3
n
—
3
X/ /T/
1
2
-
View the graph.
GRAPH
2
1
-
Find the first root.
2nd F CALC
5
2
2 Find the next root.
-
5
2nd F CALC
4 3
+ x - 5x
A
ZOOM
- 3x + 1
+ n
X/ /T/
x
n
5 2
X/ /T/
+
1
EL-9900 Graphing Calculator
2
- 3x + 1.
A A
ENTER ENTER ENTER
Display
x
Y is almost but not exactly zero.
Notice that the root found here
is an approximate value.
x
2nd F QUIT
Notes
-2.47
-0.82
6-2