Texas Instruments TI-86 - The GRAPH MATH Menu; Evaluating an Equation for a Specified T; Drawing on a Parametric Graph

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 809PARA.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.