Question
The proposition p ~ (p ~q) is equivalent to :
Options
Solution
Key Concepts and Formulas
- Implication:
- De Morgan's Law:
- Associative Law:
Step-by-Step Solution
Step 1: Rewrite the implication using the implication equivalence. We want to simplify . Using the implication rule , we can rewrite the given expression as: The reason for doing this is to get rid of the implication and work with conjunctions, disjunctions, and negations, which are easier to manipulate.
Step 2: Apply De Morgan's Law. Now, we apply De Morgan's Law to the term . De Morgan's Law states that . Therefore: Substituting this back into the expression from Step 1, we get: The reason for this step is to further simplify the expression by removing the conjunction within the negation.
Step 3: Apply the Associative Law. Since the expression now only contains disjunctions, we can apply the associative law, which states that . In our case, this means: The associative law allows us to regroup the terms without changing the meaning of the expression.
Step 4: Simplify the expression using the idempotent law. The expression is equivalent to because . Therefore: This simplification is crucial to arriving at the final answer.
Common Mistakes & Tips
- Remember the implication rule: . This is fundamental to solving these types of problems.
- Be careful when applying De Morgan's Law. Remember to negate each term inside the parentheses and change the conjunction to a disjunction (or vice versa).
- Don't forget the associative and commutative properties of logical operators, as they can simplify the expression.
Summary
We started with the expression and used the implication rule to rewrite it as . Then we applied De Morgan's Law to simplify the negated conjunction, resulting in . Finally, using the associative and idempotent laws, we simplified the expression to .
Final Answer The final answer is \boxed{(\sim p) \vee q}, which corresponds to option (A).