What's the shortcut?
Logic
Level
2
\[ (A \iff B)\iff \neg (A \Rightarrow B)\Rightarrow \neg(B\Rightarrow A) \]
Two possible ways to prove if a statement is a tautology are these:
1. Build a truth table.
2. Supposing the statement is false and concluding a contradiction or not.
Is the mathematical statement at the top a tautology?
by
Guillermo Templado