Figure 1
| First we set the function in the Y= screen
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Figure 2
| Then we set the appropriate values for the WINDOW.
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Figure 3
| Now we can GRAPH the function. This looks like the graph on page 69 of the text.
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Figure 4
| Here we add the constant function Y2 = 25 to mimic the
graph in the book.
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Figure 5
| Returning to the GRAPH, we now see both functions.
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Figure 6
| Pressing the  key starts the calculator TRACE feature.
We see, in this example, that the calculator in use is tracing
the  function and that the highlighted point has values
 .
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Figure 7
| Using the  key repeatedly to move
our trace point, we could get to the image shown here, so we see that at 5887.234 years the mass (the y value)
will be 24.523322 grams.
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Figure 8
| Moving a step to the left, we have new values and we can certainly, to the nearest 1000 years, be sure that
the correct answer is 6000. However, just for the sake of the example,
what if we wanted to know a better value for years to get 25 grams. That is, we want to know where the
two graphs intersect.
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Figure 9
| Here we returned to the original GRAPH.
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Figure 11
| Pressing the 
key sequence opens the
CALC screen shown at the left.
Then pressing the 
key selects the intersect option.
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Figure 10
| Now the calculator wants to know which two graphs to examine. This seems a bit strange since there are but two
functions defined, but it would be possible to have three or more functions
defined and then we would need to select the appropriate pair. The calculator is offering the
as the first
choice. Press the  to accept that and move
to the next screen.
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Figure 12
| Now the second function (Y2=25) is identified, again
press the key to accept that as the other function.
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Figure 13
| Here the calculator is asking us to position the highlight at a good guess. We
will use the repeatedly to move the highlight to the left,
in fact going a bit to far to arrive at the next image.
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Figure 14
| At this point we can press the key to start the search for the
point of intersection.
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Figure 15
| Here the calculator has solved the question, or at least it has given us a great approximation
to the solution with the answer being that after 5728.1425 years we would have 25 grams of carbon 14.
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