JEE Main 2021 (Online) 3rd August Morning ShiftQuestion 1
If $\square,\lozenge\in\{\wedge,\vee\}$ such that $(\sim q\wedge p)\ \square\ (q\ \lozenge\ \sim p)$ is a tautology, then
Mathematical Reasoning
Solution
$(\sim q\wedge p)\vee(q\vee\sim p)=\sim(\sim p\vee q)\vee(\sim p\vee q)$, which is a tautology. With $\wedge$ in either place it fails at some row.