Difference between permutation and combination?
Permutation and Combination:
Permutation and combination are fundamental concepts in combinatorial mathematics that deal with different ways of arranging or selecting objects from a given set. While both involve counting and arranging elements, they have distinct characteristics and are used in different scenarios.
Permutation:
Permutation refers to the arrangement of objects or elements in a specific order. It focuses on the order or sequence in which the elements are arranged. The number of permutations can vary based on the number of objects and the length of the arrangement.
Key Points:
- Permutations are concerned with the order or arrangement of elements.
- The number of permutations can vary depending on the length of the arrangement.
- Permutations are denoted using the symbol "P" and represented as nPr, where n represents the total number of objects and r represents the number of objects to be arranged.
Example:
Consider a set of three objects: A, B, and C. The possible permutations of these objects are ABC, ACB, BAC, BCA, CAB, and CBA. Notice that the order of the objects is important in permutations.
Combination:
Combination refers to the selection of objects from a given set without considering the order or arrangement. It focuses on the selection itself rather than the order in which the elements are chosen. The number of combinations can vary based on the number of objects and the selection size.
Key Points:
- Combinations are concerned with the selection of elements without considering the order.
- The number of combinations can vary depending on the selection size.
- Combinations are denoted using the symbol "C" and represented as nCr, where n represents the total number of objects and r represents the number of objects to be selected.
Example:
Consider the same set of three objects: A, B, and C. The possible combinations of these objects are AB, AC, and BC. Notice that the order of the objects is not considered in combinations.
Summary:
In summary, permutation deals with the arrangement or order of elements, while combination focuses on the selection of elements without considering the order. Permutations are concerned with the distinct order of objects, while combinations are concerned with selecting objects without regard to their order. Understanding the difference between permutation and combination is essential in various fields, such as probability, statistics, and problem-solving.