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Average Rate of Change Calculator

Find the average rate of change of a function f(x) between two x-values, with f(a), f(b) and the working.

Change the values and press Calculate to work out your own figures.

Enter f(x) and two x-values.

About function f(x)For example x^2 + 3x − 1.
About aThe first x-value (or coefficient a).
About bThe second x-value (or coefficient b).
Result
Average rate of change
5
f(a)
4
f(b)
9

f changes by 5 per unit of x on average between x = 2 and x = 3.

Show the working
  1. f(x) = x^2
  2. f(2) = 4 and f(3) = 9
  3. (f(b) − f(a)) ÷ (b − a) = (9 − 4) ÷ (3 − 2) = 5 ÷ 1 = 5

How to use it

Enter f(x) and two x-values.

Number boxes accept whole numbers, decimals, fractions (3/4), powers (2^10), roots (sqrt(2)) and the constants pi and e. Show the working lists the steps.

Key facts

(f(b) − f(a)) ÷ (b − a)

Slope of the secant

The average rate of change is the slope of the line through (a, f(a)) and (b, f(b)).

Questions

What is the average rate of change of x² from 2 to 3?

(9 − 4) ÷ (3 − 2) = 5.

Formulas

(f(b) − f(a)) ÷ (b − a)

Sources

Limitations

  • Expressions up to 500 characters; matrices up to 10 × 10.
  • Big-number results up to 100,000 digits; factorials up to 10,000!.
  • Numbers in words up to 10^102 (short scale).

Formula version 0.1.0Reviewed