Graphi Ng An I Nverse Functi On - Texas Instruments TI-89 Manual

TI 89-18
On the screen shown to the right,
activated) and
With the function highlighted, use
(and graph) on and off.

1.3.6 GRAPHI NG AN I NVERSE FUNCTI ON

function. Using the calculator graph, you can check your algebraic answer. We illustrate this
idea using the function in Example 4 of Section 1.3 of Calculus Concepts:
The fares for a cab company are determined by the function F(d) = 1.8d + 2.5 dollars where
d is the distance traveled in miles.
Press
F1 (Y
enter the function F in
variable. (Refer to Sections 1.1.2 and 1.1.3 of this Guide for
hints on how to set the window to graph this function.)
This problem does not state an interval of values for which the input variable is defined, so we
begin by guessing one that makes sense in context. Because d is the distance traveled, we
know that d ≥ 0. We choose a maximum value of 50. (Your guess is as good as the one that
is given below.)
Press
F2 (WINDOW)
appropriate values for the input and
output. Draw the graph of the function
for the view you choose with
(GRAPH).
Press
F1 (Y
Example 4 – the inverse function for F. (Your answer to part a
may or may not be the same as what is shown to the right.)
NOTE: Remember that the TI-89 requires that you use
parentheses around any numerator and/or denominator that consists of more than one symbol in
a fraction.
Press
F3 (GRAPH).
have a good view of both functions,
reset the window. Draw the TI-89's
inverse function with
Draw] 3 [DrawInv]
Press
ENTER .
function formula is not correct.
and
y 1
is turned off (i.e., deactivated).
y 2
F4 [
turns all functions on or off.
F5 [All]
clear any previously entered functions, and
),
=
Remember to use
.
y 1
and enter
F3
and enter in your answer to part a of
)
=
y 2
If you do not
2nd F1 [F6:
and type in
y 1 ( x ) .
If you do see a third graph, your inverse
are turned on (i.e.,
y 3
to toggle the check
]
b
The TI-89 can draw the graph of the inverse of a
as the input
x
as the input variable and that you use
x
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Chapter 1