Question:medium

If $p$ and $q$ are two statements, then $(p \land q) \lor (q \leftrightarrow p)$ is

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If expression varies with cases → neither tautology nor contradiction.
Updated On: Jun 17, 2026
  • tautology
  • contradiction
  • neither tautology nor contradiction
  • either tautology or contradiction
Show Solution

The Correct Option is C

Solution and Explanation

To determine whether the logical expression \((p \land q) \lor (q \leftrightarrow p)\) is a tautology, contradiction, or neither, we need to analyze it using truth tables. A tautology is an expression that is always true regardless of the truth values of its components, while a contradiction is always false. 

\(p\)\(q\)\(p \land q\)\(q \leftrightarrow p\)\((p \land q) \lor (q \leftrightarrow p)\)
TTTTT
TFFFF
FTFFF
FFFTT

Let's explain the truth table:

  • \(p \land q\) is true only when both \(p\) and \(q\) are true.
  • \(q \leftrightarrow p\) is true when \(p\) and \(q\) have the same truth value (both true or both false).
  • The expression \((p \land q) \lor (q \leftrightarrow p)\) combines these two using OR, so it is true if either of these sub-statements is true.

From the table, we observe:

  • The expression is true for (T, T) and (F, F) combinations of \(p\) and \(q\), and false for (T, F) and (F, T).

Thus, the expression \((p \land q) \lor (q \leftrightarrow p)\) is neither always true nor always false. Hence, it is neither a tautology nor a contradiction.

Therefore, the correct answer is neither tautology nor contradiction.

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