Texas Instruments TI-89 Manual Book page 148

Selecting
Parametric
Equations
Selecting the
Display Style
Tip: Use the Animate and
Path styles for interesting
projectile-motion effects.
Window Variables
Note: You can use a
negative tstep. If so, tmin
must be greater than tmax.
To graph a parametric equation, select either its
both. When you enter or edit a component, it is selected
automatically.
Selecting x and y components separately can be useful for tables as
described in Chapter 13. With multiple parametric equations, you can
select and compare all the
You can set the style for either the
you set the component to
x
sets the component to
y
The and styles are not available for parametric
Above Below
equations and are dimmed on the Y= Editor's
The Window Editor maintains an independent set of Window
variables for each
Graph
maintains independent function lists). Parametric graphs use the
following Window variables.
Variable Description
Smallest and largest
tmin, tmax
tstep Increment for the
evaluated at:
x(tmin)
x(tmin+tstep)
x(tmin+2(tstep))
... not to exceed ...
x(tmax)
, , Boundaries of the viewing window.
xmin xmax
ymin , ymax
, Distance between tick marks on the x and y axes.
xscl yscl
Standard values (set when you select
toolbar menu) are:
tmin = 0.
tmax = 2p (6.2831853... radians
or 360 degrees)
tstep =p/24 (.1308996... radians
or 7.5 degrees)
You may need to change the standard values for the
( tmin , tmax , tstep ) to ensure that enough points are plotted.
components or all the
x
x or y component. For example, if
, the
Dot TI-89 / TI-92 Plus
.
Dot
Style
mode setting (just as the Y= Editor
values to evaluate.
t
t value. Parametric equations are
y(tmin)
y(tmin+tstep)
y(tmin+2(tstep))
... not to exceed ...
y(tmax)
6:ZoomStd
xmin = ë 10.
xmax = 10.
xscl = 1.
Chapter 7: Parametric Graphing
or component or
x y
components.
y
automatically
toolbar menu.
from the „
Zoom
ymin = ë 10.
ymax = 10.
yscl = 1.
variables
t
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