Differences In Parametric And Function Graphing - Texas Instruments TI-89 Manual Book

Differences in Parametric and Function Graphing

Setting the
Graph Mode
Defining Parametric
Equations on the
Y= Editor
Note: When using t, be sure
implied multiplication is valid
for your situation.
Tip: You can use the Define
command from the Home
screen (see Appendix A) to
define functions and
equations for any graphing
mode, regardless of the
current mode.
130 Chapter 7: Parametric Graphing
This chapter assumes that you already know how to graph y(x)
functions as described in Chapter 6: Basic Function Graphing.
This section describes the differences that apply to parametric
equations.
Use 3 to set
Graph = PARAMETRIC
set Window variables. The Y= Editor and the Window Editor let you
enter information for the current
To graph a parametric equation, you must define both its
components. If you define only one component, the equation cannot
be graphed. (However, you can use single components to generate
an automatic table as described in Chapter 13.)
Be careful when using implied multiplication with
Enter: Instead of:
tù cos(60) tcos(60)
The Y= Editor maintains an independent function list for each
mode setting. For example, suppose:
¦
In graphing mode, you define a set of
FUNCTION
You change to PARAMETRIC
and components.
y
¦
When you return to
are still defined in the Y= Editor. When you return to
PARAMETRIC graphing mode, your
defined.
before you define equations or
mode setting only.
Graph
Because:
is interpreted as a user-defined
tcos
function called tcos
multiplication.
In most cases, this refers to a nonexistent
function. So the
TI-89 / TI-92 Plus
returns the function name, not a number.
graphing mode and define a set of
FUNCTION graphing mode, your
x and y
and
x y
Enter x and y components
on separate lines.
You can define
xt1(t) through xt99(t) and
yt1(t) through yt99(t).
. For example:
t
, not as implied
simply
Graph
functions.
y(x)
x
y(x) functions
components are still