User Manual

Chapter 6: Graph Tools
99
06TOOLS.DOC TI-86, Chap 6, US English Bob Fedorisko Revised: 02/13/01 2:23 PM Printed: 02/13/01 3:01 PM Page 99 of 2206TOOLS.DOC TI-86, Chap 6, US English Bob Fedorisko Revised: 02/13/01 2:23 PM Printed: 02/13/01 3:01 PM Page 99 of 22
Using dy
à
dx or TANLN
The steps for using
dy
à
dx
and
TANLN
are the same, except for the menu selection in step 1.

Select
dy
à
dx
from the
GRAPH MATH
menu.
The current graph is displayed.

Move the cursor to the function with the point for
which you want to find the derivative, or slope.
6 /
& '
# $

Move the cursor to the point (or enter the
x
value).

Solve.
♦
For
dy
à
dx
, the solution
dy
à
dx=
is displayed
and stored in
Ans
.
♦
For
TANLN
, a tangent line also is displayed.
! "
b
To remove the tangent line and
dy
à
dx=
prompt, select
CLDRW
from the
GRAPH DRAW
menu.
In the example, the function
y(x)=x^3+.3x
2
N
4x
is selected.
TANLN
(
GRAPH MATH
menu
)
and
TanLn
(
GRAPH DRAW
menu) both draw a tangent
line on the graph; only
TANLN
displays the solution,
dy
à
dx
.