Texas Instruments TI-80, Manual Book

Page: 174 / 235

11-10 Applications
You can use the parametric graphing feature of the TI
.
80 to graph the inverse
relation of any function by defining the function in X ã
T
and Y ã
T
and its inverse in
X
ä
T
and Y
ä
T
.
The function Y=.2X
3
ì
2X+6 can be expressed in parametric
form as X
T
=T and Y
T
=.2T
3
ì
2T+6.
The inverse relation of the function can be expressed in
parametric form as X
T
=F(T) and Y
T
=T. For example,
Y=.2X
3
ì
2X+6 would be expressed as X
T
=.2T
3
ì
2T+6 and
Y
T
=T.
Graph the function Y=.2X
3
ì
2X+6 and its inverse.
Follow this procedure to solve the problem.
1. Select Param , CONNECTED , and Simul modes.
2. Change the Window variable values.
Tmin= L 10 Xmin= L 15 Ymin= L 9
Tmax=10 Xmax=15 Ymax=9
Tstep=.4 Xscl=1 Yscl=5
3. Enter the expressions to define the function in parametric
form.
X1
î
=T
Y1
î
=.2T
ò
–2T+6
4. Enter the expressions to define the inverse in parametric
form.
X2 î =.2T ò –2T+6
Y2 î =T
Graphing the Inverse of a Function
Problem
Procedure