Irrational numbers are numbers that cannot be expressed as a simple fraction, meaning they cannot be written in the form \( \frac{a}{b} \), where \( a \) and \( b \) are integers and \( b \) is not zero. Instead, irrational numbers have non-repeating and non-terminating decimal expansions.
Some common examples of irrational numbers include:
- \(\pi\) (pi): The ratio of the circumference of a circle to its diameter, approximately equal to 3.14159...
- \(e\): The base of natural logarithms, approximately equal to 2.71828...
- \(\sqrt{2}\): The square root of 2, approximately equal to 1.41421..., which has been proven to be irrational.
- Golden ratio (\(\phi\)): Approximately equal to 1.61803..., it arises in various contexts including geometry and art.
In contrast, rational numbers can be represented as fractions and include integers, whole numbers, and terminating or repeating decimals.