How to Put Formulas on Calculator Ti 84 Plus

Entering Basic Formulas

The TI-84 Plus is a powerful scientific calculator that can handle complex formulas. To enter a basic formula:

1. Press the MATH key and select the appropriate operation (e.g., 1:Resultant for addition, 2:Resultant for subtraction).
2. Enter the first number.
3. Press the operation key (e.g., + for addition).
4. Enter the second number.
5. Press ENTER to see the result.

Creating Advanced Formulas

For more complex formulas, you can use the Y= editor:

1. Press the Y= key to access the equation editor.
2. Select an equation line (Y1 to Y6).
3. Enter your formula using the keypad and function keys.
4. Press ENTER to save the formula.

Using Variables

The TI-84 Plus allows you to use variables in your formulas:

• Use X for the independent variable.
• Use Y for the dependent variable.
• Use θ (Theta) for angle variables.

To set a variable:

1. Press 2ND then MODE to access the variable editor.
2. Use the arrow keys to navigate to the variable you want to set.
3. Enter the value and press ENTER.

Common Functions

The TI-84 Plus has many built-in functions:

• Trigonometric functions: sin, cos, tan, sin⁻¹, cos⁻¹, tan⁻¹
• Logarithmic functions: log, ln, eˣ
• Statistical functions: mean, median, stdDev, sum
• Financial functions: PV, PMT, FV, n

To use a function:

1. Press the 2ND key.
2. Press the appropriate function key (e.g., SIN for sine).
3. Enter the value and press ENTER.

Worked Examples

Example 1: Quadratic Formula

To solve x = (-b ± √(b² - 4ac)) / (2a):

1. Press Y= and select Y1.
2. Enter: (-b + √(b² - 4 × a × c)) / (2 × a)
3. Press ENTER.
4. Set a, b, and c values using the variable editor.
5. Press GRAPH to see the solution.

Example 2: Linear Regression

To find the line of best fit for data points:

1. Enter your data in lists L1 and L2.
2. Press STAT then CALC.
3. Select 4:LinReg(ax+b).
4. Press ENTER to see the equation.