Texas Instruments TI-73 - Manual (Page 23)

18
Using the TI-73: A Guide for Teachers Patterns and Relations
© 1998 T EXAS I NSTRUMENTS I NCORPORATED
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)
➪
Have students sketch the
graph on graph paper for
further discussions later
(slope, intercepts, how
does it describe the
situation in the problem?,
etc.).
b. Make sure the screen looks like the one shown at
the right ( TblStart=0, @ Tbl=1, Indpnt: Auto, Depend:
Auto ).
17. Use the TI-73 to show a table of values for the
equation.
- i (above the * key)
18. Compare the table on the TI-73 with the T-chart in the
first part of the activity. Ask:
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 Y 1
column represent?
(the number of beams)
19. Enter the second equation Y = 4 + 3(X - 1) in Y 2
, and
then graph it.
& # to
Y 2
Q \ [ D I T Y E *
Ask: Do you see 2 lines? Why not?