| This is especially helpful with matrices, where you may want the entries to be exact, not decimal approximations. For example, |  |
Here are some of the many other things
you can do with your calculator, in no particular order.
1. Your calculator can simplify fractions or change decimals to fractions in lowest terms. Enter the number, then follow it by 1:Frac on the Math menu.
123/567 Frac results in 41/189 23.45 Frac results in 469/20
| This is especially helpful with matrices, where you may want the entries to be exact, not decimal approximations. For example, | |
2. Zoomfit. Fitting a graph into your window could take
a lot of trial-and-error without the help of caclulus. Zoomfit,
choice 0 (after 9) on the Zoom menu, will figure out the range
for y which displays the whole graph on the x-interval you specify.
The graph should not have a vertical asymptote in the x-interval
you choose.
 |
For example, enter this function, Y1 = -x^4+5x^3+50x^2 -7. |
 |
This is what we get if we graph it using 6:ZStandard on the Zoom menu (a good way to start). Looks like there is an intercept near -5 and two more near zero. But a fourth degree polynomial like this might have a fourth intercept. |
 |
Using the same x-interval, [-10, 10], graph with Zoomfit. On the Zoom menu, press the up arrow to get to this choice, then press enter. The graph shows that the fourth intercept is near10, so all important features of the graph are shown in this window. |
 |
After observing the graph above, we can make a somewhat better-looking graph by adjusting the window settings. |
 |
Here's our final graph. Still, if we want to investigate what happens near zero, we might zoom in and make another graph. You can't always show every detail of a graph in one window. |
3 Those \ 's on the Y= menu.
If you move your cursor to the \ and then press enter
a number of times, the \ will change to one of the symbols you
see here. This will affect how the graph of the function to its
right will appear. Here we have entered the function y=x^2
on each line. Then we show the graphs of Y1, Y2, Y3 , Y4
, and Y7. Y5 and Y6 are animations you'll have to
try on your own.
4. Calculating with X found on graph.
Suppose the calculator has approximated the coordinates of some point on your graph using a command on the CALC menu and shows these on the graph. Then variables X and Y have been set to those values and can be used in future calculations.
 |
This is the graph of Y1=X^3 -4X^2 +5. The command 3:minimum from the CALC menu has been used to find the low point on the right side of the graph. |
 |
Quit the graphing page and check the values of the variables X and Y (Y is alpha-1). Even more places are show here than on the graph! X and Y will retain these values until some new values are calculated. |
5. Iteration
Suppose you have a function g and a number x0 and want to compute x1, x2, x3, ... where x1=g(x0), x2=g(x1), x3 = g(x2) ,...
a. Enter function g(x) as Y1.
b. Store x0 in X by x0 [STO] [X,T,Q,n] [ENTER] This will display x0. The value of Y1 is now g(x0) or x1. This is not yet displayed.
c. Store Y1 in X by Y1 [STO] [X,T,Q,n] [ENTER]. This will display the current value of X which is x1 and set Y1 to g(x1) or x2.
d. Now repeatedly press [ENTER]. This repeatedly executes the previous statement using new values of X, to display x2, x3, ....
For example, if x0 = 2 and
Y1 = x - (x^3-2x)/(3x^2-2) then
x1=1.6 and x4=1.414214235
