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I need to do log base 2 in long expressions such as this calculator handles. Is there a way to make it handle log base 2 instead of log base 10?

 Sep 26, 2014

Best Answer 

 #2
avatar+23247 
+13

There is a change of base formula that will allow you to change from any base to base 10:

Using common logs (that is base 10 logs):

It is: log(base) number = log(number) / log(base).

Example: If you want to find the log (in base 2) of 47:    log(base 2) 47 = log(47) / log(2)

This will work for any base:

If you want to find the log (in base 8) of 119:    log(base 8) 119 = log(119) / log(8)

This also works if you want to use natural logs:

Use the formula: log(base) number = ln(number) / ln(base).

Example: log(base 2) 47 = ln(47) / ln(2).

 Sep 26, 2014
 #1
avatar+118613 
+3

This is probably a question for Alan or maybe Ninja.  

 Sep 26, 2014
 #2
avatar+23247 
+13
Best Answer

There is a change of base formula that will allow you to change from any base to base 10:

Using common logs (that is base 10 logs):

It is: log(base) number = log(number) / log(base).

Example: If you want to find the log (in base 2) of 47:    log(base 2) 47 = log(47) / log(2)

This will work for any base:

If you want to find the log (in base 8) of 119:    log(base 8) 119 = log(119) / log(8)

This also works if you want to use natural logs:

Use the formula: log(base) number = ln(number) / ln(base).

Example: log(base 2) 47 = ln(47) / ln(2).

geno3141 Sep 26, 2014
 #3
avatar+118613 
+3

That is certainly true and that is how it is usually done but maybe the calc can handle different bases - i am not sure.   

 Sep 26, 2014
 #4
avatar+8261 
0

Remember your first answer? Guess what? geno3141 solved it, not Alan or Ninja! Lol!

 Sep 26, 2014
 #5
avatar+118613 
0

Not quite Dragon - I am wondering if the calc can handle different bases.  That is what the question really was.

 Sep 26, 2014
 #6
avatar+33616 
+5

If you hover the cursor over the log key you will see ln, ex, lg2 and 2x pop up.  lg2 is log to the base 2.

Alternatively, you can type log(x,2) where x is the number of which you want to find log to the base 2.

 Sep 27, 2014

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