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2 cards from this section. Quick, good the night before a test.
What is a counterexample?
Think of an example that disproves a general claim.
Explain proof by cases in one sentence.
No hint provided
What is a counterexample?
Think of examples that are the opposite of what the statement claims.
Using w.l.o.g. means choosing a particular case that constrains the proof.
Consider how this simplifies your reasoning.
Using w.l.o.g., prove that for any two real numbers x and y, if x + y is odd, one of them must be even.
Explore the definitions of odd and even carefully.
Show that the product of any two odd integers is odd.
Factor out to see the result!
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