Plot the tangent line to the graph of the function
f(x) = ln(x - 6)
at the point x = 8 together with the graph of this function.
Using the TI-86 graphing calculator:
- Press the GRAPH key and then pick y(x)=
by pressing the F1 key.
- If necessary, keep pressing F4 key until only
y1= appears on the screen.
- Be sure that PLOTS 1, 2 and 3 are turned-off.
- Type in
ln(x - 6)
and press the ENTER key.
- The WINDOW settings for the graph above is  [0, 12.6] × [-31/16, 31/16]:
Go to the WINDOW menu by pressing 2nd M2.
- Press the MORE key so that MATH appears in the menu.
- Press the F1 key to choose MATH.
- Press the MORE key twice so that TANLN appears
in the menu.
- Press the F3 key to choose TANLN.
- There is a blinking cursor on the graph; using the arrow
keys move this cursor along the graph so that the x value, which is indicated at the lower left hand corner of the screen is as close to 8 as
- Press the ENTER key to draw the tangent line.
- The TI-86 will draw the tangent line and display its slope across the bottom of the screen.
Constructed with the help of Chris O'Brien.