How to Graph a Function on the TI-84 Evo

The TI-84 Evo draws a graph in three steps: press Y= to open the function editor, type your function, and press graph. Everything graphing-related lives on the five keys along the top row.

Graph a function

  1. Press Y=. It's the top-left key, and it opens the function editor with the cursor sitting on Y1.
    TI-84 Evo top key row with the Y= key highlighted
    The TI-84 Evo Y= editor with an empty Y1 line
  2. Type your function. Whenever you need an X, press the X key just right of alpha. For a parabola, press the X key then the x² key so the line reads Y1=X².
    TI-84 Evo keyboard with the X,T,theta,n key highlighted next to the alpha key
    The TI-84 Evo Y= editor showing Y1 equals X squared
  3. Press graph. It's the top-right key, and the calculator draws your curve.
    TI-84 Evo top key row with the graph key highlighted
    The TI-84 Evo graphing screen showing a parabola

One thing to know: the graph screen shows a fixed slice of the coordinate plane, and it doesn't adapt to your function. Graph Y1=X+100 and you'll get an empty screen, because that line never passes through the visible area. Picking the view is what the window section below is for.

Trace along the curve

Press trace to drop a cursor onto the curve. The X and Y readout at the bottom updates as you press the left and right arrows, so you can read the value at any point. The Evo's trace also stops on points of interest and labels them, so it lands on the y-intercept first.

The TI-84 Evo trace cursor on the parabola, labeled y-intercept at X=0, Y=0

The arrows move one pixel at a time, so for anything farther away just type where you want to go: type a number while tracing, press enter, and the cursor jumps straight to that x. Typing 2 on this parabola lands the cursor on (2, 4).

The TI-84 Evo trace cursor jumped to X=2, Y=4 on the parabola after typing 2

Set the viewing window

Press window to choose exactly which part of the plane the graph shows. Xmin and Xmax are the left and right edges of the picture, Ymin and Ymax the bottom and top. The cursor starts on Xmin: type a value (it replaces the old one) and press enter to hop down to the next line. Here the window is set to show x from -5 to 5 and y from -5 up to 25:

The TI-84 Evo WINDOW screen with Xmin -5, Xmax 5, Ymin -5, Ymax 25

Press graph and it draws exactly that box. With Ymax at 25, the arc of the parabola is in view all the way up to y=25:

The TI-84 Evo graphing the parabola and line in a custom window, x from -5 to 5 and y from -5 to 25

To get a normal view back without retyping anything, press zoom and pick 6:ZStandard. It resets the graph to a standard view. The same menu has Zoom In and Zoom Out if you just want to step closer or back.

The TI-84 Evo ZOOM menu with ZStandard as option 6

Good to know

  • Graph several at once. Fill in Y2, Y3, and so on in the same editor. They all plot together, each in the color shown next to its line.
    The TI-84 Evo graphing a blue parabola and a red straight line at the same time
  • See a table instead. Press 2nd then graph and the calculator lists X values with what each function gives back, in the same colors as the curves.
    The TI-84 Evo table of values showing X, Y1, and Y2 columns
  • Nothing shows up? Make sure you used the X key for every X in the function. If the line still doesn't appear, it's probably outside the current view, like the Y1=X+100 example above: set the window to where the function actually lives.