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3.1.1 Proof (A-level only)

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Question 33

In the design of a custom optical lens, the focal length FFF is calculated as the arithmetic mean of a rational base length LLL and an irrational correction factor γ\gammaγ.

Given that F=L+γ2F = \frac{L + \gamma}{2}F=2L+γ​, prove by contradiction that the focal length FFF must be an irrational number.

[5]
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3.1.1 Proof (A-level only) Questions

  1. A Level
  2. /Maths
  3. /3.1.1 Proof (A-level only)

107 exam-style questions on WJEC A Level Maths 3.1.1 Proof (A-level only). Each one has a worked solution and a mark scheme showing where the marks go.

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