Graphing
How to Graph Equations, Adjust Window & Zoom on TI-84
Graphing is the core superpower of the TI-84. Learn how to enter functions in Y1 through Y10, configure the coordinate window, use Zoom presets and analyze curves for intersections, roots and extrema.
Step-by-step
Open the Equation Editor
Press:Y=
Press the top-left 'Y=' key directly below the screen to open the list of function slots (Y1 through Y0).
Enter Your Mathematical Equation
Press:X,T,θ,nx²-4
Use the 'X,T,θ,n' key to type the variable 'X'. For exponents, use the 'x²' button or the '^' carat key. Example: type X^2 - 4.
Tip: Always use the (-) negative key at the bottom next to ENTER for negative coefficients, NOT the subtraction operator.
Reset to Standard Window Grid
Press:ZOOM6: ZStandard
Press the 'ZOOM' button in the middle top row, then press '6' to select ZoomStandard (-10 to 10 on both X and Y axes).
View the Live Graph
Press:GRAPH
Press the 'GRAPH' button at the top right to render the curve. Use the arrow keys or press 'TRACE' to slide along points.
Calculate Zeros, Intersections & Extrema
Press:2ndTRACE (CALC)
Press [2nd] + [TRACE] to open the Calculate menu. Select '2: zero' to find roots/x-intercepts, '3: minimum' or '4: maximum' for extrema and '5: intersect' to find where two curves cross.
Tip: When prompted for Left Bound, Right Bound and Guess, arrow to position your cursor near the target point before pressing ENTER.
Generate Value Tables
Press:2ndGRAPH (TABLE)
Press [2nd] + [GRAPH] to open the Table view. You can see discrete numerical X and Y values side-by-side. To customize the step size (ΔTbl), press [2nd] + [WINDOW] (TBLSET).
Tip: Set Indpnt to 'Ask' in TBLSET to type custom X-values on demand.
| Zoom Preset | Keystroke Shortcut | Coordinate Grid Range | Best Use Case |
|---|---|---|---|
| ZStandard | [ZOOM] → 6 | X: [-10, 10], Y: [-10, 10] | Default starting view for basic polynomials, quadratics and lines |
| ZSquare | [ZOOM] → 5 | Adjusts aspect ratio so circles appear perfectly round | Geometric conic sections, circles, perpendicular line angles |
| ZTrig | [ZOOM] → 7 | X: about [-6.15, 6.15] (±47π/24), Y: [-4, 4], Xscl = π/2 | Sine, cosine and tangent curves with tick marks every π/2 (90°) |
| ZoomFit | [ZOOM] → 0 | Auto-calculates Ymin/Ymax to fit current Xmin/Xmax | Curves with huge vertical values (e.g. cubics, exponential growth) |
| ZBox | [ZOOM] → 1 | Draws an interactive bounding box with cursor | Magnifying small details, local extrema, or close asymptotes |
Common mistakes
- Using the subtraction key [-] instead of the negative sign [(-)] at the beginning of an equation, causing a SYNTAX ERROR.
- Having Stat Plot 1 turned on without list data, triggering an 'ERR: INVALID DIM' or 'ERR: DIM MISMATCH' error.
- Window limits set so Xmin is greater than or equal to Xmax, triggering 'ERR: WINDOW RANGE'.
- Forgetting to wrap complex denominators in parentheses when graphing rational functions (e.g. 1/(X-2)).
Frequently asked questions
Why is my TI-84 graph completely blank when I press GRAPH?
A blank graph usually means either: 1) your Window coordinates do not match the function (fix by pressing [ZOOM] → 6: ZStandard), or 2) the equation's '=' sign in the [Y=] menu is un-highlighted (scroll onto '=' and press ENTER to re-enable it).
How do I graph multiple equations at the same time?
Open Y=, enter your first equation in Y1, press ENTER or Down Arrow to move to Y2, enter the second equation and press GRAPH. Both curves will be drawn simultaneously with different colors on CE models.
How do I find where two graphs intersect?
Press '2nd' -> 'TRACE' (CALC), select '5: intersect', press ENTER on curve 1, ENTER on curve 2 and press ENTER for Guess.
How do I graph a vertical line like x = 4 on a TI-84?
Standard TI-84 Y= mode only graphs functions of Y in terms of X. To graph a vertical line: press [2nd] + [PRGM] (DRAW) → select '4: Vertical' → type '4' → press ENTER. Alternatively, switch to PARAMETRIC mode via [MODE]. Neither DRAW nor parametric mode is simulated on this site.
How do I turn off an equation without deleting it from Y=?
Press [Y=], move your blinking cursor over the '=' sign of the equation you want to hide and press ENTER. The highlight around '=' will disappear and the calculator will skip that function when graphing.