Sharp EL-9600c, EL-9400, EL-9650 manual Graphing Polynomials and Tracing to Find the Roots

EL-9650/9600c Graphing Calculator

Graphing Polynomials and Tracing 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 approximate the roots by using the Zoom-in and Trace features.

1. Graph the polynomial y = x 3 - 3x 2 + x + 1.

2. Approximate the left-hand root.

3. Approximate the middle root.

4. Approximate the right-hand root.

Before

Starting

There may be differences in the results of calculations and graph plotting depending on the setting. Return all settings to the default value and delete all data.

Set the zoom to the decimal window:

ZOOM

A

* (

ENTER

ALPHA

* )

7

*

Setting the zoom factors to 5 :

ZOOM

B

*

ENTER

5

ENTER

5

ENTER

2nd F

QUIT

Step & Key Operation Display Notes

*Use either pen touch or cursor to operate.

1-1

1-2

1-3

1-4

Enter the polynomial y = x 3 - 3x 2 + x + 1.

Y= EZ

5* ENTER * ENTER * ENTER *

Enter the coefficients.								It may take few seconds for
								the graph to be drawn.
2nd F		SUB
								Enter each coefficients when
								the cursor is displayed.
1	ENTER				(-)	3	ENTER
				*				*
1					1
	ENTER		*			ENTER

Return to the equation display screen.

2nd F EXE

View the graph.

GRAPH

4-1