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Algebraic Methods

Algebraic Methods

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Question 6
(a).

Assume that the sum of a rational number and an irrational number is rational:

ab+i=cd \frac{a}{b} + i = \frac{c}{d} ba​+i=dc​

where a,b,c,d a, b, c, d\,a,b,c,d are integers. Show that

i=cb−adbd i = \frac{cb - ad}{bd} i=bdcb−ad​
[3]
(b).

Hence prove by contradiction that the sum of a rational number and an irrational number is irrational

[4]
Markscheme

Algebraic Methods Questions

  1. A Level
  2. /Maths
  3. /Algebraic Methods

368 exam-style questions on Edexcel A Level Maths Algebraic Methods, covering 1.1 Proof by Contradiction, 1.2 Algebraic Fractions, 1.3 Partial Fractions, 1.4 Repeated Factors, and 1.5 Algebraic Division. Each one has a worked solution and a mark scheme showing where the marks go.

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