42 | Using the | Measurement and Geometry |
7.Ask students:
Why did we count for 2 minutes? (Ten minutes is a long time to count. Counting for 2 minutes allows you to get an average for 1 minute. Counting for 3 or 4 minutes might give a more accurate average per minute, but it might be too long for your students.)
Could you calculate the volume of each drop? (volume of water / number of drops)
How much water would be collected in 1 hour? In 1 day?
What changes to increase the total amount of water? (time)
What is the variable in this problem? (the number of hours)
8.Use the above questions to have students help you develop the formula for the following situation. Since the amount of water that would be collected changes with the number of hours you are collecting it, you could write an equation to describe this occurrence.
The volume of water equals the amount of water that would be collected in 1 hour times the number of hours.
Y= (amount of water collected in one hour) ¦ X
9.Enter the equation in the Y= editor (&).
Example If your calculation were two cups of water per hour, your equation would be Y = 2X (Z I). (See screen at the right.)
10.To view this graph, set up an appropriate, friendly viewing window.
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Enter the numbers as shown in the screen at the right. Use # to move down the fields.
(For more information about the viewing window, see “Setting the Window Format” and “Defining Window Values” in the Function Graphing chapter of the
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@X is determined by the TI- 73, depending on what you entered for Xmin and Xmax.
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