Rationalise Denominator
Maths: Edexcel A Level Pure Maths, topic 2.1.5
Rationalising the Denominator
It is often easier to work with surds when there are no square roots on the bottom of a fraction. Removing surds from the bottom of a fraction is called ‘rationalising the denominator’.
Simple example
Advanced example
- To rationalise a denominator of the form a ± √b multiply by the denominator but with the sign in front of the root changed.
Exact form
- Leaving an answer in exact form means leaving any fractions, surds and constants like in the expression rather than giving the answer as a decimal.
Test yourself on Rationalise Denominator
Which of these are in exact form?
Which of these are in exact form?
Which of these are in exact form?