Texas Instruments TI-86 - Manual (Page 111)

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 22 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 22
Using dy àdx or TANLN
The steps for using dy à dx and TANLN are the same, except for the menu selection in step 1.
ᕡ Select dy à dx from the GRAPH MATH menu.
The current graph is displayed.
ᕢ Move the cursor to the function with the point for
which you want to find the derivative, or slope.
6 /
& '
# $
ᕣ Move the cursor to the point (or enter the x
value).
ᕤ 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 .