Natural Logarithm of e is 1

Theorem

 * $\ln e = 1$

where $\ln$ is the natural logarithm, $e$ is the Euler's number, and $1$ is the identity element of multiplication.

Proof
The definition of the Euler's number as the Base of Logarithm will be used.

Then the result follows directly.

For other definitions of the Euler's number, see Equivalence of Definitions of Euler's Number.