LOG
Name
Logarithm
Description
Returns the log base Y of a number X 
.
Syntax
LOG(value1, value2)
Remarks
In the preceding equation, the value1 argument is X, and the value2 argument is Y. The second argument is optional. If you omit the value2 argument, the function assumes base 10. The number specified by the value1 argument must be a positive real number.
Data Type
Accepts numeric data. Returns numeric data. For more information, see Data Type for Each Cell Type.
Example
LOG(R1C2,R4C4)
LOG(B3,C5)
LOG(255,16)=1.9985883592