How to Graph Absolute Value Functions on the TI-84 Evo

The TI-84 Evo doesn't have an absolute value key, but it graphs absolute value functions just fine once you know where the abs( command is hiding: it's inside the MATH menu. Grab it from there, and the V-shaped graph draws the same way as any other function.

Graph an absolute value function

For this walk-through we'll graph y = |x − 3| + 1.

  1. Open the Y= list. Press y= at the top left. This is the list of functions the calculator draws. If graphing is new to you, the full walk-through is in how to graph a function on the TI-84 Evo.
  2. Grab the abs( command. Press math, arrow right once to the NUM tab, and pick 1:abs(. A pair of absolute value bars appears on the Y1 line, with the cursor sitting between them.
    The TI-84 Evo keyboard with the MATH key highlighted
    The TI-84 Evo MATH NUM menu with 1:abs( highlighted at the top
  3. Type what goes inside the bars. Press the X key (just to the right of alpha), then − and 3. Everything you type lands between the bars.
    The TI-84 Evo Y= list with X minus 3 typed inside the absolute value bars, cursor still between them
  4. Step out of the bars with the right arrow. Press ▶ (the right arrow), and the cursor hops outside the bars. Then type +1 to finish the function.
    The TI-84 Evo Y= list showing Y1 equals absolute value of X minus 3, plus 1, with the plus 1 outside the bars
  5. Press graph. There's the V. If yours matches, the entry went in right: the point of the V sits at (3, 1).
    The TI-84 Evo graphing y equals absolute value of X minus 3, plus 1, a V-shaped graph with its point at 3, 1

Good to know

  • Skip the menu with the catalog. Press 2nd then 0 for the CATALOG, an alphabetical list of every command. abs( is the very first entry, so 2nd 0 enter drops it in without any arrowing.
  • A leading negative uses the (-) key. For a function that starts with a negative, like −2|x|, the sign in front is the (-) negative key on the bottom row, not the − subtraction key. Starting a function with the subtraction key gives ERROR: SYNTAX.
  • Reading the V's point. The calculator can pin the exact coordinates of the V's point: it's the minimum of an upward V (or the maximum of a flipped one), in the same CALCULATE menu covered in how to find intercepts on the TI-84 Evo.
  • Read off exact points. To see the coordinates the V passes through as a column of numbers, see how to make a table of values on the TI-84 Evo.