Power Set and Its Elements

Master Power Sets in CBSE Class 11 Applied Mathematics. Learn to calculate the number of subsets, power set elements, and properties with solved examples.

Definition of Power Set

The power set of a set A, denoted by P(A), is the set of all possible subsets of A, including the empty set and the set A itself. If a set A contains n elements, then its power set P(A) contains 2ⁿ elements. This concept is fundamental in understanding the collection of all possible groupings within a given set.

n(P(A)) = 2ⁿ
Example: Solved Example: Find the power set of A = {1, 2}
Show Step-by-Step Solution

Step 1: Identify the elements of A, which are 1 and 2. n=2.
Step 2: List all subsets: ∅, {1}, {2}, {1, 2}.
Step 3: Enclose them in a set bracket.
Answer: P(A) = {∅, {1}, {2}, {1, 2}}

Properties of Power Sets

Every element of a power set is itself a set. For any set A, the empty set ∅ is always an element of P(A), and the set A itself is always an element of P(A). The number of elements in the power set grows exponentially as the number of elements in the original set increases.

∅ ∈ P(A) and A ∈ P(A)
Example: Solved Example: Verify n(P(A)) for A = {a, b, c}
Show Step-by-Step Solution

Step 1: Count elements in A: n=3.
Step 2: Apply formula: 2³ = 8.
Step 3: The power set will contain 8 distinct subsets.
Answer: 8 elements

Cardinality and Power Sets

The cardinality of a power set, denoted by |P(A)| or n(P(A)), is determined solely by the number of elements in the base set A. Even if the elements of A are themselves sets, the power set construction remains consistent. This property is vital for combinatorial analysis in applied mathematics.

n(P(P(A))) = 2^(2ⁿ)
Example: Solved Example: Find n(P(P(A))) for A = {1}
Show Step-by-Step Solution

Step 1: n(A) = 1.
Step 2: n(P(A)) = 2¹ = 2.
Step 3: n(P(P(A))) = 2² = 4.
Answer: 4