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The graph math menu, Evaluating an equation for a specified t, Drawing on a parametric graph – Texas Instruments TI-86 User Manual

Page 142

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130

Chapter 9: Parametric Graphing

09PARA.DOC TI-86, Chap 9, US English Bob Fedorisko Revised: 02/13/01 2:27 PM Printed: 02/13/01 3:02 PM Page 130 of 8

09PARA.DOC TI-86, Chap 9, US English Bob Fedorisko Revised: 02/13/01 2:27 PM Printed: 02/13/01 3:02 PM Page 130 of 8

The

GRAPH

ZOOM

menu items affect only the

x

window variables (

xMin

,

xMax

, and

xScl

) and

the

y

window variables (

yMin

,

yMax

, and

yScl

), except

ZSTO

and

ZRCL

, which also affect the

t

window variables (

tMin

,

tMax

, and

tStep

).

The GRAPH MATH Menu

6 / &

MATH

DRAW FORMT STGDB RCGDB

DIST

dy

à

dx

dy

à

dt

dx

à

dt

ARC

4

TANLN

dy

à

dx

Returns the derivative of

yt

divided by the derivative of

xt

dy

à

dt

Returns the derivative of the

yt

equation at a point with respect to

t

dx

à

dt

Returns the derivative of the

xt

equation at a point with respect to

t

The distances calculated by

DIST

and

ARC

are distances in the rectangular coordinate plane.

At a point where the derivative is undefined,

TANLN

will draw the line, but no result is

displayed or stored in

Ans

.

Evaluating an Equation for a Specified t

When the trace cursor is not active, the

GRAPH

menu item

EVAL

evaluates selected polar

equations directly on the graph for a given value of

t

.

eval

in a program or from the home

screen returns a list of x and y values in this form:

{

xt1(t)

yt1(t) xt2(t) xt2(t) ...

}

.

Drawing on a Parametric Graph

The

DRAW

menu items work in

Param

graphing the same as in

Func

graphing.

DRAW

instruction

coordinates in

Param

graphing are the

x

- and

y

-coordinate values of the graph screen.

The other GRAPH MATH
menu items are the same as
described in Chapter 5.