Proof by contradiction
What Proof by contradiction means in Mathematics A-Level, as defined for AQA, Pearson Edexcel, WJEC.
Definitions of Proof by contradiction
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Reference: Pearson Edexcel
Assumes the opposite and derives an impossibility, then concludes the original statement is true; classic examples prove that √2 is irrational and that there are infinitely many primes.
Assumes the logical negation of the proposition to be proved and demonstrates that this hypothesis inescapably yields a mathematical contradiction.
Assumes the opposite and derives an impossibility, stating the negation of the result and deriving a contradiction with a known fact or assumption.
Topics that use Proof by contradiction
- A: Proof (AQA A-Level)
- Proof (Pearson Edexcel A-Level)
- Proof (A2 Unit 3: Pure Mathematics B) (WJEC A-Level)
Related terms
- counter-example
- Disproof by counter example
- Irrational Number
- Proof
- Proof by deduction
- Proof by exhaustion
- Rational Number
- infinity of primes
Using Proof by contradiction in the exam
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