Sets

Which of the following sets of real numbers is such that if x is an element of the set and y is an element of the set, then the sum of x and y is an element of the set ? I. The set of negative integers II. The set of rational numbers III. The set of irrational numbers

If the number of elements in the power set of set A is 128 then find the number of elements in the set A .

Write the number of elements in the power set of null set.

Set A has 5 eleements and set B has 3 elements. Find the number of relations from set A to B.

Which of the following are examples of empty set? Set of all even prime numbers.

If A is the null set, find the number of elements in the power set P(P(A)) .