Getting started with the TI-89 (some basic settings)
Turn the calculator on. (Hit the on key. When you want the calculator off, hit the 2nd
key followed by the on key.) Adjust the contrast (if necessary) using /+ to darken
or /- to lighten the display. (That is, while pressing the key, repeatedly press
the + key to make the display darker.)
To set or change settings, hit the mode key. Here are some basic settings. (Also see the
TI-89 manual)
Graph
Choose FUNCTION in case you plan to graph a function f given a rule y = f (x).
Otherwise, choose PARAMETRIC in case you’ll be graphing a set of points (x, y)
determined from a parametric equations x = x(t) and y = y(t). Choose POLAR for
graphing an equation r = f (θ) in the polar plane.
Display digits
The default setting is FLOAT 6, which means that results are displayed to a maximum
of 6 digits. (On the other hand, FIX 6 means that 6 digits will definitely be used in
the display, regardless of the value. For example, the decimal equivalent of will show as
.250000 under the FIX 6 setting and as .25 under the FLOAT 6 setting.) You can ’FIX’
or ’FLOAT’ up to 12 digits on the TI-89.
Angle
Use RADIAN. (If you’re working with an angle in degrees, you can either switch the
setting to DEGREE or just add the degree (◦ ) “post operator” while remaining in
RADIAN setting. [Example: sin(40◦ )]
Pretty Print
Choose ON, so that any entry you make in the entry line will be echoed above in the
home screen in traditional mathematical notation.
Exact/Approx
Choose AUTO in case you’d like results to be displayed in exact symbolic form (such as
π) or in rational form (such as 5/8) where possible. Choose APPROXIMATE if you’d
like all results to be given in decimal form.
Exercise: Note that π can be entered on the TI-89 by hitting the 2nd key followed by the
∧
(exponentiation) key. Choose settings on the TI-89 that will display π to the greatest
number of decimal places possible. What value do you get?
[Answer: 3.14159265359. Use APPROXIMATE and FLOAT 12 settings.]
Do the same for the value of e. Note that the key followed by X gives ex .
[Answer: e = e∧ (1) = 2.71828182846.]