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1.4 A: Proof

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Question 89

A structural engineer calculates that the side length, sss decimetres, of a square support column must satisfy the equation s2=13s^2 = 13s2=13 to meet safety specifications.

Use proof by contradiction to prove that sss is an irrational number.

(You may assume that for any integer nnn, if n2n^2n2 is a multiple of 13, then nnn is a multiple of 13).

[6]

1.4 A: Proof Questions

  1. A Level
  2. /Maths
  3. /1.4 A: Proof

Practise AQA A Level Maths 1.4 A: Proof with exam-style questions for A Level Maths. 107 questions covering 1.4.1 Structure and methods of proof, matched to the AQA A Level Maths (7357) specification and written in Paper 1, Paper 2 and Paper 3 style. Every question includes a full worked solution and mark scheme, so you can see where marks are awarded rather than just whether you got the answer right.

Question bank

1.4 A: Proof
1.5 B: Algebra and functions
1.6 C: Coordinate geometry in the (x, y) plane
1.7 D: Sequences and series
1.8 E: Trigonometry
1.9 F: Exponentials and logarithms
1.10 G: Differentiation
1.11 H: Integration
1.12 I: Numerical methods (A-level only)
1.13 J: Vectors