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1.4.1 Structure and methods of proof

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Question 89

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

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

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

[6]

Markscheme

1.4.1 Structure and methods of proof Questions

A Level
Maths
1.4.1 Structure and methods of proof

107 exam-style questions on AQA A Level Maths 1.4.1 Structure and methods of proof. Each one has a worked solution and a mark scheme showing where the marks go.

1.4.1 Structure and methods of proof

Question bank

1.4.1 Structure and methods of proof

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Question 89

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

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

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

[6]

Markscheme

1.4.1 Structure and methods of proof Questions

A Level
Maths
1.4.1 Structure and methods of proof

107 exam-style questions on AQA A Level Maths 1.4.1 Structure and methods of proof. Each one has a worked solution and a mark scheme showing where the marks go.