Average Rate of Change Calculator

Calculate the average rate of change between two points on a function

Calculate Average Rate of Change

Coordinates of the first point

Coordinates of the second point

Results

Undefined
Average Rate of Change
Undefined - the line is vertical (infinite slope)
When x₁ = x₂, the denominator becomes zero, making the slope undefined.

Analysis

Enter coordinates for both points to see the analysis.

Example Calculation

Train Speed Example

Problem: A train travels from Paris to Rome (1420.6 km) in 12.5 hours.

Point 1: (0 hours, 0 km) - Starting point

Point 2: (12.5 hours, 1420.6 km) - End point

Solution

A = (1420.6 - 0) / (12.5 - 0)

A = 1420.6 / 12.5

A = 113.648 km/h

The train's average speed was 113.648 km/h.

Formula Reference

Average Rate of Change

A = (y₂ - y₁) / (x₂ - x₁)

A: Average rate of change

(x₁, y₁): First point coordinates

(x₂, y₂): Second point coordinates

Alternative Forms

• Δy / Δx (change in y over change in x)

• Rise over run

• Slope of secant line

Key Concepts

📈

Positive rate = function increasing on average

📉

Negative rate = function decreasing on average

➡️

Zero rate = no net change between points

⚠️

Undefined rate = vertical line (x₁ = x₂)

Understanding Average Rate of Change

What is Average Rate of Change?

The average rate of change describes how one quantity changes in relation to another over a specific interval. It represents the slope of the line connecting two points on a graph, also known as the secant line.

Real-World Applications

  • Speed: Change in distance over change in time
  • Population growth: Change in population over time
  • Economics: Change in cost per unit produced
  • Temperature: Rate of heating or cooling

Key Differences

Average vs. Instantaneous Rate

Average rate of change gives the overall rate between two points, while instantaneous rate (derivative) gives the rate at a specific point.

Slope vs. Rate of Change

For linear functions, slope and average rate of change are identical. For nonlinear functions, the average rate of change varies depending on the interval chosen.