log_nat# = LOGN( n# )
Computes the natural logarithm (to the base "e" - the Euler number).
To compute the logarith to another base use:
log_to_base_b_of_x = LOGN(x) / LOGN(b)
In order to calculate the inverse function you have to calculate EXP(l), where the EXP function can be expressed as: