A Preview of Lesson 5.4
The graphing calculator is a powerful tool that can be used to study a wide variety of graphs. In many cases, equations are graphed in the standard viewing window, [-10, 10] by [-10, 10]. To set the standard viewing window, press 6. You do not need to press after using 6.
These examples below illustrate how you can use the caluclator to graph linear relations and functions.
Example 1: Graph 2y - 6x = 8 in the standard viewing window.
First solve the equation for y. 2y - 6x = 8 2y = 6x + 8 y = 3x + 4 Then enter the equation into the calculator, set the standard viewing window, and graph. Enter: 3 + 4 (Then 6, if necessary)
First solve the equation for y.
2y - 6x = 8 2y = 6x + 8 y = 3x + 4
2y - 6x = 8
2y = 6x + 8
y = 3x + 4
Then enter the equation into the calculator, set the standard viewing window, and graph.
Enter: 3 + 4 (Then 6, if necessary)
Exercise 2: Graph y = -x + 20 in the standard viewing window
When the equation in Example 2 is graphed in the [-5, 25] by [-5, 25] viewing window, it is considered a complete graph. A complete graph shows all of the important characteristics of the graph on the screen. These include the origin and the points at which the graph crosses the x and y axes
Example 3: Use a graphing calculator to draw a graph that represents the solutions to this problem. Then list three of the soloutions.
A second number is two more than the opposite of the first.
Let x represent the first number, and let y represent the second number. The equation y = -x + 2 describes the relationship between the numbers for any first number x. Select the standard viewing window, enter the equation, and press to view the graph of the equation. A complete graph is displayed.
You can find sample solutions for the equations in two ways.
Method 1: Press the key. The cursor appears as a flasihing square and the approximate coordinates of the location of the cursor appears at the bottom of the screen. Use the right and left arrrows to move the cursor along the line. New coordinates appear for each location of the cursor. These ordered pairs are approximate solutions for the equation. Sample solutions are (0, 2) and (0.42553191, 1.5744681) Method 2: You can obtain exact solutions by pressing . A tabke if x and y values for the equation appears. Use the up and down arrow keys to scroll through the list of values. Sample solutions are (0, 2) and (3, -1)
Method 1: Press the key. The cursor appears as a flasihing square and the approximate coordinates of the location of the cursor appears at the bottom of the screen. Use the right and left arrrows to move the cursor along the line. New coordinates appear for each location of the cursor. These ordered pairs are approximate solutions for the equation. Sample solutions are (0, 2) and (0.42553191, 1.5744681)
Method 2: You can obtain exact solutions by pressing . A tabke if x and y values for the equation appears.
Use the up and down arrow keys to scroll through the list of values. Sample solutions are (0, 2) and (3, -1)
For Practice: Do Exercises at the end of section 5-4A
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