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1.1.4 Proof by contradiction (A-level only)

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Question 53

Use proof by contradiction to prove that $5\sqrt{5}$ is irrational.

(You may assume that if $n$ is an integer and $n^2$ is a multiple of 5, then $n$ is a multiple of 5).

[6]

Markscheme

1.1.4 Proof by contradiction (A-level only) Questions

A Level
Maths
1.1.4 Proof by contradiction (A-level only)

107 exam-style questions on OCR A Level Maths 1.1.4 Proof by contradiction (A-level only). Each one has a worked solution and a mark scheme showing where the marks go.

1.1.4 Proof by contradiction (A-level only)

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1.1.4 Proof by contradiction (A-level only)

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Question 53

Use proof by contradiction to prove that $5\sqrt{5}$ is irrational.

(You may assume that if $n$ is an integer and $n^2$ is a multiple of 5, then $n$ is a multiple of 5).

[6]

Markscheme

1.1.4 Proof by contradiction (A-level only) Questions

A Level
Maths
1.1.4 Proof by contradiction (A-level only)

107 exam-style questions on OCR A Level Maths 1.1.4 Proof by contradiction (A-level only). Each one has a worked solution and a mark scheme showing where the marks go.