Course home

1.1 Proof by Contradiction

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92

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

1.1 Proof by Contradiction Questions

A Level
Maths
1.1 Proof by Contradiction

107 exam-style questions on Edexcel A Level Maths 1.1 Proof by Contradiction. Each one has a worked solution and a mark scheme showing where the marks go.

1.1 Proof by Contradiction

Question bank

1.1 Proof by Contradiction

Easy Medium Hard

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

1.1 Proof by Contradiction Questions

A Level
Maths
1.1 Proof by Contradiction

107 exam-style questions on Edexcel A Level Maths 1.1 Proof by Contradiction. Each one has a worked solution and a mark scheme showing where the marks go.