Graphing Polynomials And Jumping To Find The Roots - Sharp EL9600C - Graphing Calculator Handbook

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.
There may be differences in the results of calculations and graph plotting depending on the setting.
Before
Return all settings to the default value or to delete all data.
Start
Setting the zoom factors to 5 :
Step & Key Operation
(When using EL-9600)
*Use either pen touch or cursor to operate.
1
1
-
Enter the polynomial
4 3 2
y = x + x - 5x
n
Y= a b 4
X/ /T/
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 - 5x
+ x
A
ZOOM ENTER
*
(When using EL-9600)
- 3x + 1
+
n
X/ /T/
*
n x 2
5
X/ /T/
1
EL-9600/9400 Graphing Calculator
2 - 3x + 1.
A A
ENTER ENTER 2nd F QUIT
Display
x -2.47
Y is almost but not exactly zero.
Notice that the root found here
is an approximate value.
x -0.82
Notes
4-2