How to Find the Vertex on TI 84 Calculator

Quadratic functions create a curved graph called a parabola. One of the most important points on this graph is the vertex, which represents the highest or lowest point of the parabola. Many math problems require students to find this point accurately.

While the vertex can be calculated using algebra, the TI 84 graphing calculator provides a faster method using graph analysis tools. By graphing the quadratic function and using the calculator’s built-in features, students can quickly identify the vertex.

What You Need Before Starting

Before finding the vertex, make sure the calculator is ready.

TI 84 Calculator Compatibility

This method works for:

TI 84
TI 84 Plus
TI 84 Plus CE

All models include the same graph analysis tools.

Required Calculator Settings

Before starting:

Calculator should be in Function mode
The equation must be entered in the Y= screen
The graph window should display the full parabola

Correct window settings help identify the vertex clearly.

Math Prerequisites

You should understand:

Quadratic equations in the form y = ax² + bx + c
Basic graph interpretation
Maximum and minimum points on graphs

No advanced algebra techniques are required.

How to Use the TI-84 Calculator to Find a Vertex

The TI 84 graphing calculator includes a minimum and maximum calculation tool that helps locate the vertex.

Depending on the direction of the parabola:

If the parabola opens upward, the vertex is a minimum point
If the parabola opens downward, the vertex is a maximum point

The calculator identifies this point automatically when using graph analysis.

Step-by-Step: Find the Vertex on TI 84

We will use the quadratic function:

y = x² − 4x + 3

Step 1: Enter the Equation

Press Y=
Type X^2 - 4X + 3
Press ENTER

The equation is now stored.

Step 2: Display the Graph

Press GRAPH
A parabola should appear

If the graph is not clear:

Press ZOOM
Select 6:ZStandard

This resets the graph window.

Step 3: Open the Calculation Menu

Press 2nd
Press TRACE

This opens the CALC menu.

Step 4: Choose Minimum or Maximum

If the parabola opens upward:

Select 3:Minimum

If the parabola opens downward:

Select 4:Maximum

Step 5: Identify the Vertex

The calculator will ask for:

Left bound
Right bound
Guess

Move the cursor around the vertex area and press ENTER for each prompt.

The calculator will display the vertex coordinates.

Understanding the Vertex Result

The vertex is displayed as:

(x, y)

Where:

x represents the horizontal position
y represents the minimum or maximum value

This point is the turning point of the parabola.

Common Mistakes and How to Fix Them

• Vertex not visible on screen

Cause: Graph window range is incorrect.

Fix: Use Zoom Standard or adjust window settings.

• Using the wrong calculation option

Cause: Choosing maximum instead of minimum (or vice versa).

Fix: Check whether the parabola opens upward or downward.

• Incorrect equation entry

Cause: Missing exponent or incorrect signs.

Fix: Re-enter the quadratic function carefully.

Using the Online TI-84 Tool

You can also practice finding vertices using the TI 84 Calculator Tool available on this website.

The online calculator allows you to:

Enter quadratic equations
Graph parabolas instantly
Use graph analysis features
Practice identifying vertex points

The vertex is a key feature of any quadratic graph. Instead of solving equations manually, the TI 84 graphing calculator provides built-in tools that quickly identify the vertex. By entering the equation, graphing the function, and using the calculator’s minimum or maximum option, students can easily locate the vertex coordinates.