User Guide

Chapter 9: Split Screen 137
Chapter 9:
Split Screen
Getting Started: Exploring the Unit Circle
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 † † † † ~ Í 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.
6. Press y - and change
Indpnt to Ask.