Laws of logarithms

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Laws of logarithms

• IB SL/HL
• Adrian Sparrow
• www.ibmaths.com

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Logarithms
Logarithms were invented by John Napier as
another form of writing indices.
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The rules of logarithms
From your answers suggest a simplification for
log a - log b
1. Use your calculator to find
3. Use your calculator to find
From your answers suggest a simplification for
log a log b
From your answers suggest a simplification for
nlog a
2. Use your calculator to find
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Change of base rule
Start with x
Write as an index
Take a log of both sides
Use the power rule
Leave x on its own.
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The Laws of Logarithms