Find the counterexample
Claim: for all real a,b, sqrt(a+b)=sqrt(a)+sqrt(b).
- One valid counterexample refutes a universal claim.
- Apply the method to this new case and check the strongest alternative.
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02
PRACTICE MISSIONdefinitions, logic, counterexample, rigor, and exposition
definitions, logic, counterexample, rigor, and exposition
Which choice refutes it?
MODELProof Blueprint
MATH
PROVEChoose with evidence
CLUE
Pause. Find what matters. Then make your move.