Texas Instruments TI-89 Voyage 200, User Manual

Page: 387 / 1008

3D Graphing 387
How the Viewing Angle Is Measured
How the Viewing Angle Is Measured How the Viewing Angle Is Measured
How the Viewing Angle Is Measured
Note:
When
eye
ψ
=0
, the z axis is vertical on the screen. When
eye
ψ
=90
, the z axis is
rotated 90
¡
counterclockwise and is horizontal.
In the Window Editor (
8 $
), always enter
eye q
,
eye f
, and
eye
ψ
in degrees,
regardless of the current angle mode.
The viewing angle has three components:
•
eye q
— angle in degrees from the
positive x axis.
•
eye f
— angle in degrees from the
positive z axis.
•
eye
ψ
— angle in degrees by which the
graph is rotated counter-clockwise
around the line of sight set by
eye q
and
eye
f
.
Y
Z
X
eye
q
eye
f
eye
Do not enter a ¡ symbol. For
example, type 20, 70, and
0, not 20
¡ , 70 ¡ and 0 ¡ .