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If p always speaks against q, then p R...

If p always speaks against q, then ` p Rightarrow p vv ~ q ` is

A

a tautology

B

contradiction

C

contingency

D

none of these

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The correct Answer is:
To solve the problem, we need to analyze the statement "If p always speaks against q, then \( p \Rightarrow (p \lor \neg q) \)". ### Step-by-Step Solution: 1. **Understanding the Statement**: - The statement "p always speaks against q" implies that whenever p is true, q must be false. This can be represented as \( p \Rightarrow \neg q \). 2. **Rewriting the Implication**: - The expression we need to analyze is \( p \Rightarrow (p \lor \neg q) \). - Recall that \( p \Rightarrow r \) can be rewritten as \( \neg p \lor r \). Therefore, we can rewrite our expression: \[ p \Rightarrow (p \lor \neg q) \equiv \neg p \lor (p \lor \neg q) \] 3. **Simplifying the Expression**: - The expression \( \neg p \lor (p \lor \neg q) \) can be simplified using the associative property of disjunction: \[ \neg p \lor p \lor \neg q \] - The term \( \neg p \lor p \) is always true (this is known as the Law of Excluded Middle). Thus, we have: \[ \text{True} \lor \neg q \] - Since anything ORed with true is true, we conclude: \[ \neg p \lor (p \lor \neg q) \equiv \text{True} \] 4. **Conclusion**: - The expression \( p \Rightarrow (p \lor \neg q) \) is always true, which means it is a tautology. ### Final Answer: The expression \( p \Rightarrow (p \lor \neg q) \) is a **tautology**.
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OBJECTIVE RD SHARMA ENGLISH-MATHEMATICAL REASONING -Chapter Test
  1. Which of the following sentences is a statement ?

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  2. The property ~ ( p ^^ q) -= ~ p vv ~ q is called

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  3. When does the inverse of the statement ~ p Rightarrow q results in T...

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  4. which of the following is a contradiction ?

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  5. In which of the following is equivalent cases, p Rightarrow q is fal...

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  6. Which of the following is equivalent to p Rightarrow q ?

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  7. Which of the following pairs are logically equivalent ?

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  8. Which of the following is Contingency?

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  9. The statement p vv q is

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  10. Which of the following is a tautology ?

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  11. The statement p Rightarrow p vv q

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  12. what are the truth values of ( ~ p Rightarrow ~ q) and ~( ~ p Rightar...

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  13. If truth values of p vv q is ture,then truth value of ~ p ^^ q is

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  14. If p and q are two statements, then p vv ~ ( p Rightarrow ~ q) is ...

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  15. The contrapositive of statement ~ p Rightarrow ( p ^^ ~ q) is

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  16. ~ [ ~ p ^^ ( p harr q)] -= is equivalent to

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  17. If a compound statement r is contradiction , then the truth value of ...

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  18. When does the value of the statement (p ^^ r) harr ( r ^^ q) become...

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  19. If p always speaks against q, then p Rightarrow p vv ~ q is

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  20. Which of the following connectives satisfy commutatiive law ?

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