Irrational number意思

"Irrational number" is a mathematical term that refers to a number that cannot be expressed as a ratio of two whole numbers, or in other words, it cannot be written as a simple fraction. These numbers are usually non-repeating and non-terminating decimals.

The most famous irrational number is π (pi), which is the ratio of the circumference of a circle to its diameter. Other examples of irrational numbers include the square root of 2, the golden ratio (approximately 1.618033989), and the square root of any number that is not a perfect square.

Irrational numbers are different from rational numbers, which are numbers that can be expressed as the quotient of two integers, with the second integer not being zero. For example, 1/2, 3, 7/8, and -5 are all rational numbers.