How to Graph Trig Functions on the TI-83 Plus

By C. C. Edwards

The TI-83 Plus graphing calculator has built-in features especially designed for graphing trigonometric functions. They produce graphs that look like graphs you see in text books; and when you trace these graphs, the x-coordinate of the tracing point is always given as a fractional multiple of


To use these features when graphing trigonometric functions, follow these steps:

  1. Put the calculator in Function and Radian mode.

    Press [MODE]. In the third line, highlight Radian, and in the fourth highlight Func. (To highlight an item in the Mode menu, use the


    keys to place the cursor on the item, and then press [ENTER].)

  2. Enter your trigonometric functions into the Y= editor.

  3. Press [ZOOM][7] to graph the function.

    [ZOOM][7] invokes the ZTrig command which graphs the function in a viewing window in which




    It also sets the tick marks on the x-axis to multiples of


    When you trace a function graphed in a ZTrig window, the x-coordinate of the trace cursor will be a multiple of