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How Do You Convert From Exponential Form to Natural Logarithmic Form?
Write ex = 9 in natural logarithmic form.
Summary
- 'e' is called the 'natural base' and is approximately equal to 2.71828
- You can change between exponential form and logarithmic form
- 'b' stands for the base
- 'x' represents the exponent
- 'log' is short for 'logarithm'
- '
≈ ' means 'approximately equal to' - 'ln' stands for natural log
- logex is usually written as 'ln(x)'
- ln(9) = x is ex = 9 in natural logarithmic form

Notes
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- A logarithm is the opposite, or inverse, of an exponential expression
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- The exponential expression y = bx is equivalent to the logarithmic expression x = logby
- logby = x is asking, 'What number 'x' do we need to raise 'b' to in order to get 'y'?'
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- A natural logarithm is just a logarithm whose base is the natural base 'e'
- 'e' is an irrational number approximately equal to 2.71828
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- If y = ex, then x = logey
- 'e' is NOT a variable -- it's always equal to the same irrational number, which we can approximate to 2.71828
- 'e' is also known as the 'natural base'
- logey is usually written as 'ln(x)'
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- The base of a logarithm is always the same as the base of its corresponding exponential expression
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- The base of an exponential function is always the number that's being raised to a power
- Here we're raising 'e' to the 'x' power, so 'e' is our base
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- In exponential form, the exponent is always the power that some number is being raised to
- Here we're raising 'e' to the 'x' power, so the 'x' is our exponent
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- 'y' is what the exponential expression is equal to
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- We usually write 'ln' instead of 'loge
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- 9, the number the exponential expression is equal to, goes inside the logarithm
- We end up with 'ln(9) = x'