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AS Unit 1 Pure Mathematics A

Quick questions on Mathematical proof: deduction, exhaustion and counterexample - WJEC A-Level Maths

4short Q&A pairs drawn directly from our worked dot-point answer. For full context and worked exam questions, read the parent dot-point page.

What is proof by deduction?
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A direct or deductive proof chains together known facts and definitions in logically valid steps until you reach the required conclusion. The key skill at this level is to represent the objects generally so that the argument covers every case, not just one example.
What is q1?
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Prove by deduction that the sum of three consecutive integers is divisible by 33. [3 marks]
What is q2?
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Disprove: "for all real xx, x2>xx^2 > x". [2 marks]
What is q3?
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Use exhaustion to show that no perfect square ends in the digit 77. [3 marks]

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