In algebra and calculus, you will often need to find an equation of a tangent line to a curve at a particular point. The TI-86 will draw a tangent line at a specified point. However, only the line is drawn; no values can be found. For analytical purposes, it is easier and better to use TANLN. The notation is TanLn(expression, x). You access it by pressing .
Enter on the home screen. Press ENTER.