Math Problem Statement

  1. Use truth tables to determine if the following propositions are equivalent. [3] (a) ¬(p → ¬q) ⇔ p ∧ q [3] (b) ¬p ∧ q ⇔ ¬(p → ¬q)

Solution

Let's analyze each part of the problem step by step, using truth tables to determine if the propositions are logically equivalent.

(a) ¬(p → ¬q) ⇔ p ∧ q

  1. Construct truth table for each part:
    • p → ¬q: This is the conditional statement "if p, then not q."
    • ¬(p → ¬q): This is the negation of "p → ¬q."
    • p ∧ q: This is the conjunction of "p" and "q."

The truth table for p,q,p¬q,¬(p¬q),pqp, q, p \to \neg q, \neg (p \to \neg q), p \land q:

pqp → ¬q¬(p → ¬q)p ∧ q
TTFTT
TFTFF
FTTFF
FFTFF

Analysis:

  • For each truth value assignment to pp and qq, the columns for ¬(p¬q)¬(p → ¬q) and pqp ∧ q match exactly.
  • Therefore, ¬(p¬q)\neg(p \to \neg q) is logically equivalent to pqp \land q.

(b) ¬p ∧ q ⇔ ¬(p → ¬q)

  1. Construct truth table for each part:
    • ¬p ∧ q: This is the conjunction of "not p" and "q."
    • ¬(p → ¬q): This is the negation of "p → ¬q" (from the previous part).

The truth table for p,q,¬p,¬pq,p¬q,¬(p¬q)p, q, \neg p, \neg p \land q, p \to \neg q, \neg (p \to \neg q):

pq¬p¬p ∧ qp → ¬q¬(p → ¬q)
TTFFFT
TFFFTF
FTTTTF
FFTFTF

Analysis:

  • For each truth value assignment to pp and qq, the columns for ¬pq¬p ∧ q and ¬(p¬q)¬(p → ¬q) match exactly.
  • Therefore, ¬pq\neg p \land q is logically equivalent to ¬(p¬q)\neg(p \to \neg q).

Final Conclusion:

  • (a) ¬(p¬q)pq¬(p → ¬q) ⇔ p ∧ q is true.
  • (b) ¬pq¬(p¬q)¬p ∧ q ⇔ ¬(p → ¬q) is true.

Both propositions are logically equivalent as shown by the truth tables.

Would you like further details or clarification?


Here are 5 related questions:

  1. How can logical equivalence be proven without a truth table?
  2. What are common logical equivalences involving conditionals and negations?
  3. Can De Morgan’s laws help in simplifying logical propositions?
  4. How does logical implication (\to) relate to conjunction (\land) and disjunction (\lor)?
  5. Why is negating a conditional statement tricky in logical reasoning?

Tip: When working with conditional statements, translating them into equivalent expressions can simplify complex logical propositions.

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Math Problem Analysis

Mathematical Concepts

Logic
Truth Tables
Logical Equivalence
Negation
Conjunction
Implication

Formulas

p → q: Implication
¬p: Negation
p ∧ q: Conjunction
Truth table construction to verify logical equivalence

Theorems

Logical equivalence verification using truth tables
Properties of implication and negation
De Morgan's Laws

Suitable Grade Level

Grades 10-12