Algebra 2 Decoding Logarithms
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Logs
Decoding Logarithms

 

 Remember what logs mean?

 

 
 We can write this another way ...

 

 
 Notice something? They both mean exactly the same thing!
 

 X = log10Y is the exact same statement as 10X = Y

 
 Now graphing something like:

 X = log10Y

 
 Might seem pretty tough, but graphing

 10X = Y

 
 seems a lot easier.
 
 So when you need to graph a log equation,
 read the meaning of the equation 
 and then write it as an exponential equation.
 And graph that ...
 
 Of course, this works both ways.
 If we had an exponent equation
 we could read the meaning of that,
 and write it as a log equation.
 
 So if we have ...

 

 
 if we want to we can write as:

 

 
 Why would we want to?
 Who knows!
 
 Example:
 Change Y = ln X
 to an exponential equation ...
 
 Remember that ln means "loge" and "e" is just a number (about 2.7)
 
 So:

 

 
 Becomes ...

 

 

   copyright 2005 Bruce Kirkpatrick

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