Skip to main content
Differentiation
Lesson 1 of 11
Introduction

Differentiation from first principles

Objective. Derive a gradient function using the limit definition.

  1. 1. Learn
  2. 2. Worked example
  3. 3. Practice
  4. 4. Feedback
  5. 5. Continue

Learn: the key idea

The derivative is the limit of the gradient of a chord as the two points move together: f′(x) = lim(h→0) [f(x+h) − f(x)] / h.

Worked example

Differentiate f(x) = x² from first principles.

f′(x) = 2x
Illustrated card showing f′(x) = 2x
  1. 1f(x+h) − f(x) = (x+h)² − x² = 2xh + h².
  2. 2Divide by h: 2x + h.
  3. 3Let h → 0.

Answer: f′(x) = 2x

Concept mastery

Based on your past attempts at this lesson — the question types to practise again come first.

Complete a practice set to see your concept breakdown here.

Practice

Practice happens on its own screen, one question at a time. Answers stay hidden until you submit yours, and you can stop and pick up at the same question later.

Start practising

Your progress

Tick each step as you finish it. Your exact reading position is saved automatically, so Continue drops you back on the same line.

0 of 4 steps complete

Your place saves automatically as you read.

My dashboard