| The Problem |
|
The
linear function given by |
The number 10000 in this
problem represents the value of 
. So replacing
with 10000 gives us the following equation to solve:
10000 = 214.2 (x – 1950) + 2322 |
To solve
the equation numerically we use the TABLE feature
on the calculator. First, the equation to be solved must be entered in 
as in Intersection of Graphs Method. Press
and then enter 10000 (the left side of the equation) for
and enter
214.2 (X – 1950) + 2322 (the right side of the equation) for
. On your
calculator you should see:
To create a table press 2nd
then WINDOW [TBLSET] to set up the necessary parameters.
Enter 1980 for TblStart, and enter 1 for 
.
Make sure that both boxes are over the word AUTO and not over
the word ASK. If the box is on ASK, arrow down to the line
and press ENTER as the box is blinking on AUTO.
Now press 2nd
and then GRAPH [TABLE] and the table will appear.
Looking in the column, find the value that is closest
to 10000. This value is 10033 which
corresponds to the year X = 1986.0. Thus X 
1986 since this is where and
are closest to being equal. (See Using
a Table to Solve Equations.)
 |
 |
In order to be more precise, once
again press 2nd and then WINDOW [TBLSET].
Enter 1985 for TblStart and 0.1 for .
We choose 1985 for a starting point since the solution appears to be after 1985
but before 1986. Then press 2nd GRAPH and another table will
appear on your screen.
|
 |
Use the down arrow
to scroll down the screen looking for the value in that is closest
to 10000. This value is 9990.4 which corresponds to
X = 1985.8. Thus, the refined solution is approximately 1985.8. This result is consistent with our
other two methods.
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© 2019, Middle Georgia State University. All rights reserved.
models the number of radio stations on the air from 1950 to 1995.
(Source: National Association of Broadcasters.) Determine an
equation whose solution is the year when there were 10000 radio stations
on the air and then solve the equation graphically, symbolically,
and numerically. 
