Question
Consider the following two propositions: If the proposition is evaluated as FALSE, then :
Options
Solution
Key Concepts and Formulas
- Implication: is FALSE only when is TRUE and is FALSE. Otherwise, it's TRUE.
- Negation: is TRUE if is FALSE, and FALSE if is TRUE.
- Conjunction: is TRUE only when both and are TRUE. Otherwise, it's FALSE.
- Disjunction: is FALSE only when both and are FALSE. Otherwise, it's TRUE.
Step-by-Step Solution
Step 1: Analyze the given condition
We are given that is FALSE. Using the truth table for implication, this means that must be TRUE and must be FALSE. This implies:
Step 2: Determine the truth value of p and q
Since , we have . Substituting this into , we get: For the disjunction to be FALSE, both terms must be FALSE. Therefore, . So, we have and .
Step 3: Evaluate proposition P1
Substitute and : Since , we have: Since , we have: Thus, P1 is FALSE.
Step 4: Evaluate proposition P2
Substitute and : Since and , we have: Thus, P2 is FALSE.
Step 5: Determine which option is correct
We found that P1 is FALSE and P2 is FALSE.
Common Mistakes & Tips
- Remember that is only FALSE when is TRUE and is FALSE. It's TRUE in all other cases.
- Pay close attention to the order of operations and the meaning of each logical connective ().
- When evaluating compound propositions, substitute the truth values of the variables and simplify step by step.
Summary
We were given that is FALSE, which implied that is TRUE and is FALSE. This allowed us to deduce that and . Substituting these values into the expressions for P1 and P2, we found that both P1 and P2 are FALSE. Therefore, the correct option is that both P1 and P2 are FALSE.
Final Answer
The final answer is \boxed{C}, which corresponds to option (C).