I Ntersecti On Method - Texas Instruments TI-89 Manual

TI 89-14
The value of the leftmost x-intercept has
the x-coordinate
Repeat the above procedure to find the
rightmost x-intercept. Confirm that it is
where
= 4.25.
x
NOTE: If this process does not return the correct value for the intercept that you are trying to
find, you have probably not included the place where the graph crosses the axis between the two
bounds (i.e., between the and marks on the graph.)

I NTERSECTI ON METHOD

Press
F1 (Y
one side of the equation, 3x – 0.8x
of the equation, 2.3, in
Draw the graphs with
If you use the former, press
[ZoomStd].
reset to
ymax 8
(If you reset the window,
To locate where
[Math] 5 [Intersection].
to mark the first curve. The cursor
jumps to the other function – here, the
line. Next, press
second curve.
Note that the number corresponding to the location of each
function appears on the top left of the screen as the cursor moves
from the curve to the line. Next, press
the left of the intersection point you want to find – in this case,
the leftmost point. Press
Use to move the cursor to the right of the intersection point
►
you are finding to supply the upper bound for that point. The
point of intersection must lie between the two markers for the
lower and upper bounds. Press
The value of the leftmost x-intercept has
the x-coordinate
Repeat the above procedure to find the
rightmost x-intercept. Confirm that it is
where
= 4.25.
x
−
= 0.5.
x
for solving the equation f(x) = c:
and clear all locations with
)
=
2
+ 4, in
.
y 2
F2 [Zoom] 4 [ZoomDec] or F2 [Zoom] 6
to get a better view of the top of the graph.
F3 (GRAPH)
, press
= F5
y 1 y 2
Press
ENTER
to mark the
ENTER
ENTER .
ENTER .
−
= 0.5.
x
Enter
CLEAR .
and the other side
y 1
and
F2 (WINDOW)
redraws the graph.)
to move the cursor to
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Chapter 1