Texas Instruments TITANIUM TI-89 - Manual (Page 387)

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 ¡ .