Texas Instruments TI-86 - Manual (Page 142)

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.