Leave lesson

Pure · Integration

Chapter 1 · 4

The idea

Integrating with partial fractions

Splitting a rational function into partial fractions so each piece integrates to a logarithm — turning an impossible-looking fraction into a sum of ln terms.

A full journey — read it, play with it, work it, then earn real exam marks. Everything stays on the timeline below.

In this lesson — start anywhere

Pure · Integration

Integrating with partial fractions

Splitting a rational function into partial fractions so each piece integrates to a logarithm — turning an impossible-looking fraction into a sum of ln terms.

Why it works

Split, then integrate

A fraction like 3x+5(x+1)(x+3)\dfrac{3x + 5}{(x + 1)(x + 3)} has no standard integral as it stands — the bottom isn't the derivative of anything tidy, so the reverse chain rule won't bite. But you already know how to break such a fraction into partial fractions, and each piece is something you can integrate. That fraction is the lesson's running example; by the worked examples it will be two logs.

Each piece is a log

The key fact is that a single partial fraction integrates straight to a logarithm:

∫Aax+b dx=Aaln⁡∣ax+b∣+c\int \frac{A}{ax + b}\,dx = \frac{A}{a}\ln|ax + b| + c

Keep reading — free

The rest of the explanation, plus 3 worked examples you step through move by move.

Start free

Takes a minute — no card.