Syntax: @LN(X)
X = a numeric value greater than 0
@LN returns the log base e of X. The inverse of @LN is the exponentiation function @EXP.
Examples:
@LN(6) = 1.7917595
@LN(@EXP(X4)) = 10, where X4 = 10
@LN(-1) = Error - @LN, domain is x > 0