Topic 1 HL · Number & Algebra · €35

IB MATHEMATICS AA · HIGHER LEVEL · PREMIUM

Methods of Proof

A story-led Higher Level proof chapter that keeps the language simple and mathematical. It develops direct proof, counterexamples and contradiction before moving into irrational roots, irrational logarithms, integer-solution arguments and polynomial questions with no integer zeros.

THE MAIN IDEA

Choose the proof method before doing the algebra.

The chapter is written as a mathematical story rather than a formal-logic sheet. Students learn what they are allowed to assume, what they must show, how a single counterexample destroys a universal claim, and how contradiction works by temporarily assuming the opposite and forcing an impossibility.

DIRECT PROOF

Start from what is given

Translate even, odd, rational and divisibility statements into algebra and move forward logically.

COUNTEREXAMPLE

One example can be enough

Disprove universal claims efficiently while respecting every condition in the question.

CONTRADICTION

Assume the opposite

Use parity, prime factors and rational forms to force an impossible conclusion.

HL SYNTHESIS

Irrationality + integer zeros

Work with roots, logarithms and polynomial structures in longer exam-style proofs.

INSIDE THE PACK

Proof explained slowly, then tested seriously.

LECTURE NOTES

12 pages

Narrative teaching, many worked examples and three adapted IB-style proof questions at the end.

WORKSHEET

52 questions · 7 pages

Direct proof, counterexamples, contradiction, irrationality, logarithms and difficult integer-zero arguments.

WORKED SOLUTIONS

7 pages

Detailed reasoning for the full worksheet, written in the same natural proof language as the notes.

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Included in Topic 1 HL · Number & Algebra · €35

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NEXT HL PROOF UNIT

Mathematical Induction

Continue with the separate induction chapter after mastering the proof methods in this pack.

Return to the HL resource library →
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