Texas Instruments TI-83 Getting Started: Exploring the Unit Circle

9-2 Split Screen
8309SPLT.DOC TI-83 international English Bob Fedorisko Revised: 02/19/01 12:31 PM Printed: 02/19/01 1:36
PM Page 2 of 6
Getting Started is a fast-paced introduction. Read the chapter for details.
Use G.T (graph-table) split-screen mode to explore the unit circle and its
relationship to the numeric values for the commonly used trigonometric angles
of 0°, 30°, 45°, 60°, 90°, and so on.
1. Press z to display the mode screen.
Press † † ~ Í to select Degree
mode. Press † ~ Í to select Par
(parametric) graphing mode.
Press † † † † ~ ~ Í to select G.T
(graph-table) split-screen mode.
2. Press y [FORMAT] to display the format
screen. Press † † † † † ~ Í to
select ExprOff.
3. Press o to display the Y= editor for Par
graphing mode. Press ™ „ ¤
Í to store cos(T) to X1T. Press ˜
„ ¤ Í to store sin(T) to Y1T.
4. Press p to display the window
editor. Enter these values for the window
variables.
Tmin=0 Xmin=L2.3 Ymin=L2.5
Tmax=360 Xmax=2.3 Ymax=2.5
Tstep=15 Xscl=1 Yscl=1
5. Press r. On the left, the unit circle is
graphed parametrically in Degree mode
and the trace cursor is activated. When
T=0 (from the graph trace coordinates),
you can see from the table on the right
that the value of X1T (cos(T)) is 1 and Y1T
(sin(T)) is 0. Press ~ to move the cursor to
the next 15° angle increment. As you trace
around the circle in steps of 15°, an
approximation of the standard value for
each angle is highlighted in the table.
Getting Started: Exploring the Unit Circle