Operation Manual

Chapter 9: Split Screen 140
Chapter 9:
Split Screen
Getting Started: Exploring the Unit Circle
Getting Started is a fast-paced introduction. Read the chapter for details.
Use
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 Parametric graphing mode.
Press † † † † ~ ~ Í to select Graph-Table
split-screen mode.
2. Press y .
to display the format screen. Press †
† † † † † ~ Í to select
ExprOff.
3. Press o to display the Y= editor for
Parametric
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=L3Ymin=L2.5
Tmax=360 Xmax=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.
6. Press y - and change
Indpnt to Ask.