Practice question · True or false
A conditional and its contrapositive always have the same truth value.
Hints
- Compare their truth tables row by row.
- This equivalence is what licenses proof by contrapositive.
Show the answer
True
Why
True. 'If p then q' and 'if NOT q then NOT p' agree in all four rows, which is exactly why proving the contrapositive proves the original. The converse and inverse enjoy no such guarantee.
Practise Proof by Contradiction and Contrapositive
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