Nov 2006

1
Rationalise the Denominator
These are usually short questions that require
you to multiply the numerator and denominator by
the surd so as to rationalise the denominator.
Below are a couple of examples from previous
papers. The following slide gives four examples
Nov 2007 Rationalise the denominator 2 v5
Nov 2006 Rationalise 1 v2 v2
2
1. Rationalise the denominator a) 2 b) 3
c) 1 v3 d) 4 v11 v5 v7 v3
v11

• Multiply top and bottom by the surd
• v5 ? (2v5)/5
• (3v7)/7
• ((1 v3) x v3)/3 ? (v3 3)/3
• ((4 v11) x v11)/11 ? (4v11 11)/11