Permutation Formula

In permutation calculations, the order of the objects is important. The number of ways to arrange r objects from a set of n distinct objects (without repetition) is given by the permutation formula, which is the ratio of the factorial of n to the factorial of the difference between n and r. Factorial, represented by the exclamation mark (!), means the product of an integer and all the integers below it down to 1. For example, 5! equals 5 × 4 × 3 × 2 × 1 equals 120. The permutation formula can be written in function form in JavaScript, where a loop calculates the product of descending numbers from n to n - r. This formula is useful in various fields including statistics, probability theory, and combinatorial problems such as scheduling, cryptography, and decision-making processes.