A logarithm #log_a(x)# is the value fulfilling the equation #a^(log_a(x))=x#.

#ln# represents the natural logarithm, that is, the logarithm with base #e#. To solve, then, we can isolate #ln(x)# and then apply the exponential function. As #ln(x)# is the same as #log_e(x)#, then #e^ln(x) = x#.