Simplify or prove logarithmic identity

Show that one logarithmic expression is equivalent to another by applying laws of logarithms, no equation to solve.

6 questions · Moderate -0.1

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CAIE P2 2019 June Q1
3 marks Moderate -0.8
1 Show that \(\ln \left( x ^ { 3 } - 4 x \right) - \ln \left( x ^ { 2 } - 2 x \right) \equiv \ln ( x + 2 )\).
OCR MEI C2 2007 June Q6
5 marks Moderate -0.8
6
  1. Write down the values of \(\log _ { a } 1\) and \(\log _ { a } a\), where \(a > 1\).
  2. Show that \(\log _ { a } x ^ { 10 } - 2 \log _ { a } \left( \frac { x ^ { 3 } } { 4 } \right) = 4 \log _ { a } ( 2 x )\).
Edexcel AEA 2003 June Q6
19 marks Challenging +1.8
6.(a)Show that $$\sqrt { 2 + \sqrt { 3 } } - \sqrt { 2 - \sqrt { 3 } } = \sqrt { 2 }$$ (b)Hence prove that $$\log _ { \frac { 1 } { 8 } } ( \sqrt { 2 + \sqrt { 3 } } - \sqrt { 2 - \sqrt { 3 } } ) = - \frac { 1 } { 6 } .$$ (c)Find all possible pairs of integers \(a\) and \(n\) such that $$\log _ { \frac { 1 } { n } } ( \sqrt { a + \sqrt { 15 } } - \sqrt { a - \sqrt { 15 } } ) = - \frac { 1 } { 2 } .$$
OCR C3 2012 June Q2
6 marks Moderate -0.5
2 It is given that \(p = \mathrm { e } ^ { 280 }\) and \(q = \mathrm { e } ^ { 300 }\).
  1. Use logarithm properties to show that \(\ln \left( \frac { \mathrm { e } \mathrm { p } ^ { 2 } } { q } \right) = 261\).
  2. Find the smallest integer \(n\) which satisfies the inequality \(5 ^ { n } > p q\).
AQA AS Paper 2 2019 June Q4
4 marks Moderate -0.8
4 Show that, for \(x > 0\) $$\log _ { 10 } \frac { x ^ { 4 } } { 100 } + \log _ { 10 } 9 x - \log _ { 10 } x ^ { 3 } \equiv 2 \left( - 1 + \log _ { 10 } 3 x \right)$$
OCR MEI Paper 3 2019 June Q7
4 marks Standard +0.3
7 In this question you must show detailed reasoning.
  1. Express \(\ln 3 \times \ln 9 \times \ln 27\) in terms of \(\ln 3\).
  2. Hence show that \(\ln 3 \times \ln 9 \times \ln 27 > 6\).