Sharp EL9900 manual Solving a System of Equations by Graphing or Tool Feature

EL-9900 Graphing Calculator

Solving a System of Equations by Graphing or Tool Feature

A system of equations is made up of two or more equations. The calculator provides the Calculate feature and Tool feature to solve a system of equations. The Calculate feature finds the solution by calculating the intersections of the graphs of equations and is useful for solving a system when there are two variables, while the Tool feature can solve a linear system with up to six variables and six equations.

Example

Solve a system of equations using the Calculate or Tool feature. First, use the Calcu- late feature. Enter the equations, draw the graph, and find the intersections. Then, use the Tool feature to solve a system of equations.

1. Solve the system using the Calculate feature.

{y = 2x

2.Solve the system using the Tool feature.y = x 2 - 1

{-3x+ y = -55x+ y = 1

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 viewing window to “-5 < X < 5”, “-10 < Y < 10”.

WINDOW (-) 5 ENTER 5 ENTER

As the Tool feature is only available on the Advanced keyboard, example 2 does not apply to the Basic keyboard.

Step & Key Operation Display Notes

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1-2

1-3

1-4

Enter the system of equations

y = x 2 - 1 for Y1 and y = 2x for Y2.

Y= X//T/n x2 — 1 ENTER

2X//T/n

View the graphs.

GRAPH

Find the left-hand intersection using the Calculate feature.

2nd F CALC 2

Find the right-hand intersection by accessing the Calculate feature again.

2nd F CALC 2

Note that the x and y coordi- nates are shown at the bot- tom of the screen. The answer is : x = - 0.41 y = - 0.83

The answer is : x = 2.41 y = 4.83

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