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Press
(
F4
TRACE
along the graph of the equation in y
Press
to jump from the graph of y
y
. Tracing reveals that guesses for the input values
2
where these two graph intersect are x »
Return to the home screen with
Access the SOLVER and enter the equation y
as shown on the right. Enter the guess for the left-
most intersection point and solve for x.
Enter the guess for the rightmost intersection point
and solve for x.
The two solutions to the equation, reported to four
decimal places, are x =
1.2.3 GRAPHICALLY FINDING INTERCEPTS
the vertical and horizontal axis can be done graphically as well as by the methods
indicated in 1.2.2 of this Guide. Remember the process by which we find intercepts:
¥ To find the y-intercept of a function y = f(x), set x=0 and solve the resulting equation.
¥ To find the x-intercept of a function y = f(x), set y=0 and solve the resulting equation.
Also remember that an x-intercept of a function y = f(x) has the same value as the root or
solution of the equation f(x) = 0.
Clear all locations in the y(x)= list and enter in y
2
f(x) = 4x Ð x
Ð 2.
Draw a graph with
(
or
F2
RANGE
good view of all intercepts. Press
Even though it is very easy to find f(0) =
have the calculator find the y-intercept while view-
ing the graph by pressing
TI-85
MORE
TI-86
MORE
Both
View the y-intercept f(0) =
Copyright © Houghton Mifflin Company. All rights reserved.
) and use
and/or
.
1
1
2nd
EXIT
–
10.5774 and x = 3.7462.
(
)
F3
ZOOM
MORE
) and reset yMin to - 6 for a
WIND
F5
(
)
F1
MATH
MORE
F4
(
)
F1
MATH
MORE
F2
–
2.
to move
to the graph of
10.6, x »3.8.
–
(
) .
QUIT
= y
1
2
Finding where a function graph crosses
1
(
) . Press
F4
ZDECM
(
) .
GRAPH
–
2, you can
(
)
YICPT
(
)
YICPT
B-15
Chapter 1
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