Permutations, Combinations, & Set Theory

Front

What is a permutation?

Back

A permutation is an arrangement of objects in a specific order. The order matters in permutations.

Front

What is a combination?

Back

A combination is a selection of objects where the order does not matter. It is used when choosing items from a larger set.

Front

What is the formula for permutations of n items taken r at a time?

Back

The formula is nPr = n! / (n - r)!.

Front

What is the formula for combinations of n items taken r at a time?

Back

The formula is nCr = n! / (r! * (n - r)!).

Front

Define the universal set.

Back

The universal set is the set that contains all possible elements for a particular discussion or problem.

Front

What is the complement of a set A?

Back

The complement of a set A, denoted A', is the set of all elements in the universal set that are not in A.

Front

If U = {1, 2, 3, 4, 5} and A = {2, 3}, what is A'?

Back

A' = {1, 4, 5}.

Front

What does the intersection of two sets A and B represent?

Back

The intersection of two sets A and B, denoted A ⋂ B, is the set of elements that are common to both A and B.

Front

If A = {1, 2, 3} and B = {2, 3, 4}, what is A ⋂ B?

Back

A ⋂ B = {2, 3}.

Front

What does the union of two sets A and B represent?

Back

The union of two sets A and B, denoted A ∪ B, is the set of all elements that are in A, in B, or in both.