Rationalize denominator simple

A question is this type if and only if it asks to rationalize a denominator of the form a/(b + c√d) or a/(b - c√d) by multiplying by the conjugate, resulting in the form p + q√r.

79 questions · Easy -1.1

1.02b Surds: manipulation and rationalising denominators
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OCR C1 2012 January Q1
4 marks Easy -1.2
1 Express \(\frac { 15 + \sqrt { 3 } } { 3 - \sqrt { 3 } }\) in the form \(a + b \sqrt { 3 }\), where \(a\) and \(b\) are integers.
OCR C1 2009 June Q2
4 marks Easy -1.2
2 Express \(\frac { 8 + \sqrt { 7 } } { 2 + \sqrt { 7 } }\) in the form \(a + b \sqrt { 7 }\), where \(a\) and \(b\) are integers.
OCR C1 2010 June Q3
5 marks Easy -1.2
3
  1. Express \(\frac { 12 } { 3 + \sqrt { 5 } }\) in the form \(a - b \sqrt { 5 }\), where \(a\) and \(b\) are positive integers.
  2. Express \(\sqrt { 18 } - \sqrt { 2 }\) in simplified surd form.
OCR C1 2015 June Q1
3 marks Easy -1.2
1 Express \(\frac { 8 } { \sqrt { 3 } - 1 }\) in the form \(a \sqrt { 3 } + b\), where \(a\) and \(b\) are integers.
OCR C1 2016 June Q2
4 marks Easy -1.2
2 Express \(\frac { 3 + \sqrt { 20 } } { 3 + \sqrt { 5 } }\) in the form \(a + b \sqrt { 5 }\).
OCR MEI C1 2010 January Q5
5 marks Easy -1.2
5
  1. Find the value of \(144 ^ { - \frac { 1 } { 2 } }\).
  2. Simplify \(\frac { 1 } { 5 + \sqrt { 7 } } + \frac { 4 } { 5 - \sqrt { 7 } }\). Give your answer in the form \(\frac { a + b \sqrt { 7 } } { c }\).
OCR MEI C1 2013 January Q7
5 marks Moderate -0.8
7
  1. Express \(\sqrt { 48 } + \sqrt { 75 }\) in the form \(a \sqrt { b }\), where \(a\) and \(b\) are integers.
  2. Simplify \(\frac { 7 + 2 \sqrt { 5 } } { 7 + \sqrt { 5 } }\), expressing your answer in the form \(\frac { a + b \sqrt { 5 } } { c }\), where \(a , b\) and \(c\) are integers.
OCR MEI C1 2016 June Q5
5 marks Easy -1.2
5
  1. Express \(\sqrt { 50 } + 3 \sqrt { 8 }\) in the form \(a \sqrt { b }\), where \(a\) and \(b\) are integers and \(b\) is as small as possible.
  2. Express \(\frac { 5 + 2 \sqrt { 3 } } { 4 - \sqrt { 3 } }\) in the form \(c + d \sqrt { 3 }\), where \(c\) and \(d\) are integers.
OCR MEI AS Paper 1 2018 June Q1
2 marks Easy -1.2
1 Write \(\frac { 8 } { 3 - \sqrt { 5 } }\) in the form \(a + b \sqrt { 5 }\), where \(a\) and \(b\) are integers to be found.
OCR MEI AS Paper 1 2019 June Q3
4 marks Moderate -0.8
3 Given that \(k\) is an integer, express \(\frac { 3 \sqrt { 2 } - k } { \sqrt { 8 } + 1 }\) in the form \(a + b \sqrt { 2 }\) where \(a\) and \(b\) are rational expressions in terms of \(k\).
OCR MEI AS Paper 1 2022 June Q1
3 marks Easy -1.2
1 Rationalise the denominator of the fraction \(\frac { 2 + \sqrt { n } } { 3 + \sqrt { n } }\), where \(n\) is a positive integer.
OCR MEI AS Paper 2 2024 June Q4
3 marks Easy -1.2
4 In this question you must show detailed reasoning.
Express \(\frac { 1 + 4 \sqrt { 3 } } { 2 + \sqrt { 3 } }\) in the form \(\mathrm { a } + \mathrm { b } \sqrt { 3 }\), where \(a\) and \(b\) are integers to be determined.
OCR MEI Paper 1 2020 November Q2
3 marks Easy -1.2
2 Express \(\frac { a + \sqrt { 2 } } { 3 - \sqrt { 2 } }\) in the form \(\mathrm { p } + \mathrm { q } \sqrt { 2 }\), giving \(p\) and \(q\) in terms of \(a\).
OCR MEI Paper 3 2023 June Q3
3 marks Moderate -0.3
3 In this question you must show detailed reasoning.
Find the value of \(k\) such that \(\frac { 1 } { \sqrt { 5 } + \sqrt { 6 } } + \frac { 1 } { \sqrt { 6 } + \sqrt { 7 } } = \frac { k } { \sqrt { 5 } + \sqrt { 7 } }\).
AQA C1 2009 January Q3
7 marks Easy -1.2
3
  1. Express \(\frac { 7 + \sqrt { 5 } } { 3 + \sqrt { 5 } }\) in the form \(m + n \sqrt { 5 }\), where \(m\) and \(n\) are integers.
  2. Express \(\sqrt { 45 } + \frac { 20 } { \sqrt { 5 } }\) in the form \(k \sqrt { 5 }\), where \(k\) is an integer.
AQA C1 2011 January Q2
5 marks Easy -1.2
2
  1. Simplify \(( 3 \sqrt { 3 } ) ^ { 2 }\).
  2. Express \(\frac { 4 \sqrt { 3 } + 3 \sqrt { 7 } } { 3 \sqrt { 3 } + \sqrt { 7 } }\) in the form \(\frac { m + \sqrt { 21 } } { n }\), where \(m\) and \(n\) are integers.
AQA C1 2013 January Q3
8 marks Easy -1.3
3
    1. Express \(\sqrt { 18 }\) in the form \(k \sqrt { 2 }\), where \(k\) is an integer.
    2. Simplify \(\frac { \sqrt { 8 } } { \sqrt { 18 } + \sqrt { 32 } }\).
  1. Express \(\frac { 7 \sqrt { 2 } - \sqrt { 3 } } { 2 \sqrt { 2 } - \sqrt { 3 } }\) in the form \(m + \sqrt { n }\), where \(m\) and \(n\) are integers.
AQA C1 2011 June Q2
8 marks Easy -1.2
2
    1. Express \(\sqrt { 48 }\) in the form \(k \sqrt { 3 }\), where \(k\) is an integer.
    2. Simplify \(\frac { \sqrt { 48 } + 2 \sqrt { 27 } } { \sqrt { 12 } }\), giving your answer as an integer.
  1. Express \(\frac { 1 - 5 \sqrt { 5 } } { 3 + \sqrt { 5 } }\) in the form \(m + n \sqrt { 5 }\), where \(m\) and \(n\) are integers.
AQA C1 2012 June Q1
4 marks Moderate -0.8
1 Express \(\frac { 5 \sqrt { 3 } - 6 } { 2 \sqrt { 3 } + 3 }\) in the form \(m + n \sqrt { 3 }\), where \(m\) and \(n\) are integers.
(4 marks)
AQA C1 2014 June Q2
4 marks Moderate -0.8
2 A rectangle has length \(( 9 + 5 \sqrt { 3 } ) \mathrm { cm }\) and area \(( 15 + 7 \sqrt { 3 } ) \mathrm { cm } ^ { 2 }\).
Find the width of the rectangle, giving your answer in the form \(( m + n \sqrt { 3 } ) \mathrm { cm }\), where \(m\) and \(n\) are integers.
[0pt] [4 marks]
AQA C1 2016 June Q2
5 marks Easy -1.3
2
  1. Simplify \(( 3 \sqrt { 5 } ) ^ { 2 }\).
  2. Express \(\frac { ( 3 \sqrt { 5 } ) ^ { 2 } + \sqrt { 5 } } { 7 + 3 \sqrt { 5 } }\) in the form \(m + n \sqrt { 5 }\), where \(m\) and \(n\) are integers.
    [0pt] [4 marks]
OCR MEI Paper 3 2024 June Q4
2 marks Moderate -0.8
4 In this question you must show detailed reasoning. Determine the exact value of \(\frac { 1 } { \sqrt { 2 } + 1 } + \frac { 1 } { \sqrt { 3 } + \sqrt { 2 } } + \frac { 1 } { 2 + \sqrt { 3 } }\).
AQA C1 2008 January Q3
7 marks Easy -1.2
3
  1. Express \(5 \sqrt { 8 } + \frac { 6 } { \sqrt { 2 } }\) in the form \(n \sqrt { 2 }\), where \(n\) is an integer.
  2. Express \(\frac { \sqrt { 2 } + 2 } { 3 \sqrt { 2 } - 4 }\) in the form \(c \sqrt { 2 } + d\), where \(c\) and \(d\) are integers.
AQA C1 2007 June Q2
7 marks Easy -1.2
2
  1. Express \(\frac { \sqrt { 63 } } { 3 } + \frac { 14 } { \sqrt { 7 } }\) in the form \(n \sqrt { 7 }\), where \(n\) is an integer.
  2. Express \(\frac { \sqrt { 7 } + 1 } { \sqrt { 7 } - 2 }\) in the form \(p \sqrt { 7 } + q\), where \(p\) and \(q\) are integers.
AQA C1 2009 June Q2
7 marks Easy -1.2
2
  1. Express \(\frac { 5 + \sqrt { 7 } } { 3 - \sqrt { 7 } }\) in the form \(m + n \sqrt { 7 }\), where \(m\) and \(n\) are integers.
  2. The diagram shows a right-angled triangle. The hypotenuse has length \(2 \sqrt { 5 } \mathrm {~cm}\). The other two sides have lengths \(3 \sqrt { 2 } \mathrm {~cm}\) and \(x \mathrm {~cm}\). Find the value of \(x\).