Ekuation

Math

Rate of Change Calculator

Instantaneous Rate of Change via Derivatives

The rate of change tells you how fast one quantity changes relative to another. The instantaneous rate of change is the derivative of the function at a specific point. This calculator computes both the symbolic derivative and its numeric value at any x-value you choose.

Enter a math expression using standard notation. Use * for multiplication, ^ for exponents.

Variable of differentiation. For partial derivatives, change to y, z, etc.

Numerically evaluate f(x) and f'(x) at a specific x-value and show the tangent line.

Derivative Calculator Tips

Click to show tips

Try an Example

Pick a scenario to see how the calculator works, then adjust the values

Power Rule

Differentiate a polynomial using the power rule.

Key values: f(x) = x^3 - 2x^2 + x · 1st derivative

Chain Rule

Differentiate a composite function with sin(x^2).

Key values: f(x) = sin(x^2) · Chain rule applied

Product Rule with Tangent

Differentiate exp(x)*cos(x) and evaluate the tangent at x = 0.

Key values: f(x) = exp(x)*cos(x) · Tangent at x = 0

Second Derivative

Compute the second derivative to analyze concavity.

Key values: f(x) = x^4 - 6x^2 + 4 · 2nd derivative

Documentation

This calculator is also known as Rate of Change Calculator.

Read the complete guide

Rate of Change in Physics

In physics, velocity is the rate of change of position: v(t) = ds/dt. Acceleration is the rate of change of velocity: a(t) = dv/dt. This calculator finds these rates symbolically and evaluates them at any time t.

Rate of Change in Economics

Marginal cost is the rate of change of total cost: MC(q) = dC/dq. Marginal revenue is the rate of change of total revenue. These derivatives tell economists how costs and revenues change as production changes.

Examples

Physics: Velocity from Position

A particle has position s(t) = t^3 - 3t^2 + 2t. Find velocity at t = 2.

v(t) = 3t^2 - 6t + 2. At t = 2: v(2) = 12 - 12 + 2 = 2.

Key takeaway: The derivative of position gives velocity at any instant.

Economics: Marginal Cost

Total cost C(q) = 0.01q^2 + 5q + 100. Find marginal cost at q = 50.

MC(q) = 0.02q + 5. At q = 50: MC(50) = 1 + 5 = 6.

Key takeaway: Marginal cost tells you the cost of producing one additional unit.

Applying Rate of Change

Use derivatives to understand real-world rates:

  • Identify what quantities are changing and which variable drives the change
  • Write the relationship as a function, then differentiate
  • Evaluate the derivative at specific points for concrete answers

Frequently Asked Questions about Rate of Change Calculator

What is the difference between average and instantaneous rate of change?

Average rate of change is the slope of the secant line between two points: [f(b) - f(a)] / (b - a). Instantaneous rate of change is the derivative f'(a), which is the slope of the tangent line at a single point.

How is rate of change used in real life?

Rate of change appears everywhere: speed (rate of position change), acceleration (rate of velocity change), population growth rate, interest rates, and marginal cost/revenue in economics.

Specialized Calculators

Choose from 4 specialized versions of this calculator, each optimized for specific use cases and calculation methods.

Related Calculators

6 Calculators

More Math calculators

Calculator Search

Search and find calculators