Join IDNLearn.com and start exploring the answers to your most pressing questions. Ask your questions and receive comprehensive and trustworthy answers from our experienced community of professionals.

Prove the following properties for any three sets:

[tex]\[ A \cap (B \cup C) = (A \cap B) \cup (A \cap C) \][/tex]
and
[tex]\[ A \cup (B \cap C) = (A \cup B) \cap (A \cup C) \][/tex]


Sagot :

Sure, let's work through the given set identities step by step.

### First Property: [tex]\( A \cap (B \cup C) = (A \cap B) \cup (A \cap C) \)[/tex]

To prove this, we need to show that an element [tex]\( x \)[/tex] belongs to the set on the left-hand side if and only if it belongs to the set on the right-hand side.

Proof:

1. Suppose [tex]\( x \in A \cap (B \cup C) \)[/tex].

- By the definition of intersection, [tex]\( x \in A \)[/tex] and [tex]\( x \in B \cup C \)[/tex].
- By the definition of union, [tex]\( x \in B \cup C \)[/tex] means that [tex]\( x \in B \)[/tex] or [tex]\( x \in C \)[/tex].

Therefore, we have two cases:
- If [tex]\( x \in B \)[/tex], then [tex]\( x \in A \cap B \)[/tex].
- If [tex]\( x \in C \)[/tex], then [tex]\( x \in A \cap C \)[/tex].

Thus, [tex]\( x \in (A \cap B) \cup (A \cap C) \)[/tex].

2. Conversely, suppose [tex]\( x \in (A \cap B) \cup (A \cap C) \)[/tex].

- By the definition of union, [tex]\( x \in (A \cap B) \cup (A \cap C) \)[/tex] means that [tex]\( x \in A \cap B \)[/tex] or [tex]\( x \in A \cap C \)[/tex].

Therefore, we have two cases:
- If [tex]\( x \in A \cap B \)[/tex], then [tex]\( x \in A \)[/tex] and [tex]\( x \in B \)[/tex].
- If [tex]\( x \in A \cap C \)[/tex], then [tex]\( x \in A \)[/tex] and [tex]\( x \in C \)[/tex].

- In either case, we have [tex]\( x \in A \)[/tex] and [tex]\( x \in B \cup C \)[/tex].

Thus, [tex]\( x \in A \cap (B \cup C) \)[/tex].

Since both directions have been shown, we conclude that [tex]\( A \cap (B \cup C) = (A \cap B) \cup (A \cap C) \)[/tex].

### Second Property: [tex]\( A \cup (B \cap C) = (A \cup B) \cap (A \cup C) \)[/tex]

To prove this, we need to show that an element [tex]\( x \)[/tex] belongs to the set on the left-hand side if and only if it belongs to the set on the right-hand side.

Proof:

1. Suppose [tex]\( x \in A \cup (B \cap C) \)[/tex].

- By the definition of union, [tex]\( x \in A \cup (B \cap C) \)[/tex] means that [tex]\( x \in A \)[/tex] or [tex]\( x \in B \cap C \)[/tex].
- If [tex]\( x \in B \cap C \)[/tex], then [tex]\( x \in B \)[/tex] and [tex]\( x \in C \)[/tex].

Therefore, we have two cases:
- If [tex]\( x \in A \)[/tex], then [tex]\( x \in A \cup B \)[/tex] and [tex]\( x \in A \cup C \)[/tex].
- If [tex]\( x \in B \cap C \)[/tex], then [tex]\( x \in B \)[/tex] and [tex]\( x \in C \)[/tex], implying that [tex]\( x \in A \cup B \)[/tex] and [tex]\( x \in A \cup C \)[/tex].

Thus, [tex]\( x \in (A \cup B) \cap (A \cup C) \)[/tex].

2. Conversely, suppose [tex]\( x \in (A \cup B) \cap (A \cup C) \)[/tex].

- By the definition of intersection, [tex]\( x \in (A \cup B) \cap (A \cup C) \)[/tex] means that [tex]\( x \in A \cup B \)[/tex] and [tex]\( x \in A \cup C \)[/tex].

Therefore, we have two cases:
- If [tex]\( x \in A \)[/tex], then [tex]\( x \in A \)[/tex] which satisfies the left-hand side.
- If [tex]\( x \notin A \)[/tex], then [tex]\( x \in B \)[/tex] (as [tex]\( x \in A \cup B \)[/tex] and [tex]\( x \notin A \)[/tex]) and [tex]\( x \in C \)[/tex] (as [tex]\( x \in A \cup C \)[/tex] and [tex]\( x \notin A \)[/tex]), which implies [tex]\( x \in B \cap C \)[/tex].

In either case, we have [tex]\( x \in A \cup (B \cap C) \)[/tex].

Since both directions have been shown, we conclude [tex]\( A \cup (B \cap C) = (A \cup B) \cap (A \cup C) \)[/tex].

By showing both properties step by step with logical deductions, we have proven the set identities.
Your engagement is important to us. Keep sharing your knowledge and experiences. Let's create a learning environment that is both enjoyable and beneficial. Your questions find clarity at IDNLearn.com. Thanks for stopping by, and come back for more dependable solutions.