How to Adjust the Graphing Window on the TI-84 Evo

The window decides how much of a graph the TI-84 Evo's screen shows, and you can set each of its four edges yourself.

Here's the graph of Y1 = X² − 16 in the window the calculator starts with. The bottom of this parabola is cut off. (New to graphing? Graphing a function on the TI-84 Evo covers typing it in.)

The TI-84 Evo graph of Y1 equals X squared minus 16 in the starting window, with the bottom of the curve cut off

Drawn in full, with the calculator's window as a box, you can see the part that's missing:

A drawing of the whole curve y equals x squared minus 16 with the calculator's window as a box; the bottom of the curve hangs below the box and is marked cut off

Find how low the curve goes

  1. Press 2nd, then graph. TABLE is the blue label above the graph key. It lists X values down the left and what the function gives back for each one, starting at X = 0.
    The TI-84 Evo table for Y1 starting at X equals 0, where Y is negative 16 and the values below it climb back up

The bottom of this parabola sits on the y-axis, where x is 0, and the table shows y = −16 there. So the bottom of the window needs to sit a little lower than that. −20 works.

Move the bottom of the window

Here is what each WINDOW setting controls:

A labeled diagram of the graphing window: Xmin is the left edge, Xmax the right edge, Ymin the bottom edge and Ymax the top edge, with Xscl and Yscl brackets marking the space between tick marks
  1. Press window. It's the second key on the top row.
    The TI-84 Evo top row of keys with the window key highlighted
    The WINDOW screen opens with the cursor on Xmin.
    The TI-84 Evo WINDOW screen with its starting values, Xmin negative 15.9 and Ymin negative 10.4
  2. Press the down arrow until the cursor lands on Ymin. That's the bottom edge.
  3. Type −20 and press enter. Make the minus sign with the (−) key on the bottom row. What you type replaces the old value.
    The TI-84 Evo WINDOW screen with Ymin changed to negative 20 and every other setting unchanged
  4. Press graph. Now the bottom of this parabola fits on the screen.
    The TI-84 Evo graph of Y1 equals X squared minus 16 with the window's bottom at negative 20, showing the whole narrow parabola

Spread the curve across the screen

There's still a lot of empty space on the left and right, though. Bringing Xmin and Xmax in closer makes it fit better, and lines at x = −6 and 6 hug it nicely:

A drawing of the parabola inside the calculator's window after the bottom fix, with dashed blue lines at x equals negative 6 and 6 hugging the curve
  1. Press window again. The cursor starts on Xmin, the left edge.
  2. Type −6 and press enter. The cursor moves down to Xmax.
  3. Type 6 and press enter. That's the right edge.
    The TI-84 Evo WINDOW screen with Xmin negative 6, Xmax 6 and Ymin negative 20
  4. Press graph. The curve spreads out to fill the screen, bottom and all.
    The TI-84 Evo graph of Y1 equals X squared minus 16 in the window x from negative 6 to 6 and y from negative 20 to 10.4, filling the screen

Good to know

  • ERROR: SYNTAX after typing a negative edge? The subtract key was used instead of (−). On the WINDOW screen the two signs look almost the same, but only the negative key works. Choose 2:Go to to land back on the WINDOW screen and retype the number.
  • An axis that turns into a thick black bar means the scale is too small for the window. Here the y-axis runs from −1000 to 1000 with Yscl left at 1, which asks for 2,000 tick marks. Raising Yscl to 100 spaces them out again.
    A TI-84 Evo graph with Ymin negative 1000, Ymax 1000 and Yscl 1, where the y-axis is drawn as a thick black bar
  • Back to the starting window: press zoom and choose 4. It's called Zoom Default on OS 7.1 and ZDecimal before that, and both put the window back to where the calculator started.
  • ΔX changes by itself. The calculator works it out from Xmin and Xmax, so the long number at the bottom of the WINDOW screen updates on its own when you set a new window.