18 | Using the | Patterns and Relations |
14.Turn off STAT PLOTS, and then display the graph.
- e Q b *
15.Ask:
What do you notice about the graph on the screen?
What is the value of Y when X is 57? How can you find out? (Press ) to see the values on the graph. If you are not tracing whole number values for X, estimate the value of Y by rounding the decimal.)
What will Y equal when X is 57? (To find the whole number value, press R J b.)
Is this the same value you found earlier when you added 3 to each previous term? When you used the @ key? When you used the b key?
16.Since the X values in the table of values for the equation depend on some initial settings in the TABLE SETUP, do the following.
a.Access the TABLE SETUP screen.
- f (above the ' key)
b.Make sure the screen looks like the one shown at the right (TblStart=0, @Tbl=1, Indpnt: Auto, Depend: Auto).
17.Use the
- i (above the * key)
18.Compare the table on the
What value does the table give for X = 57?
How does this compare to the value you computed earlier for X = 57?
What do the X values in the table represent? (the length of the wall)
What do the numbers in the Y1 column represent? (the number of beams)
19.Enter the second equation Y = 4 + 3(X - 1) in Y2, and then graph it.
& # to Y2 Q \ [ D I T Y E *
Ask: Do you see 2 lines? Why not?
➪Have students sketch the graph on graph paper for
further discussions later (slope, intercepts, how does it describe the situation in the problem?, etc.).
© 1998 TEXAS INSTRUMENTS INCORPORATED