Texas Instruments TI-89 Manual Book page 141

Finding the
Derivative (Slope) at
a Point
Finding the
Numerical Integral
over an Interval
Tip: Typing x values is a
quick way to set the limits.
Tip: To erase the shaded
area, press † (ReGraph).
Finding an Inflection
Point within an
Interval
124 Chapter 6: Basic Function Graphing
1. From the Graph screen, press ‡ and select
select from the submenu.
1:dy/dx
2. As necessary, use D and C to select the applicable function.
3. Set the derivative point.
Either move the cursor to the
point or type its x value.
4. Press ¸.
The derivative at that point is
displayed.
1. From the Graph screen, press ‡ and select
2. As necessary, use D and C to select the applicable function.
3. Set the lower limit for
to the lower limit or type its
4. Press ¸. A 4 at the top of the screen marks the lower limit.
5. Set the upper limit, and press
¸.
The interval is shaded, and its
approximate numerical
integral is displayed.
1. From the Graph screen, press ‡ and select
2. As necessary, use D and C to select the applicable function.
3. Set the lower bound for
to the lower bound or type its
4. Press ¸. A 4 at the top of the screen marks the lower bound.
5. Set the upper bound, and
press ¸.
The cursor moves to the
inflection point (if any) within
the interval, and its
coordinates are displayed.
. Either use A and B to move the cursor
x
value.
x
. Either use A and B to move the cursor
x
value.
x
. Then
6:Derivatives
‰
7: f(x)dx .
.
8:Inflection