Surds・Form 3 maths

Rationalise a denominator √b

A standard method from Surds: the steps and worked examples.

Steps

Multiply top and bottom by √b, because √b × √b = b.

Example 1: Rationalise 6/√3.

= 6√3 / (√3 × √3)
= 6√3 / 3
= 2√3

For the whole topic, read Surds: key points, common mistakes and how the DSE tests it.