What is a rational or irrational number?

1 Answer
Trevor Ryan.
Mar 28, 2016

A rational number is one that can be written as an integer over an integer, with non-zero denominator. ie. all your fractions.

The set of rational numbers is hence given in set notation as

QQ={m/n;m,n in ZZ; n!=0}

An irrational number cannot be expressed as a ratio of integers and include numbers such as pi, e, sqrt2, ln2, etc.
The set of irrational numbers =RR-QQ.

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