What will be the dimension of $x$ in $e^x$?

Question

I just want to know if in an exponential function $e^x$, will $x$ always be dimensionless? If so, Why?

Answer 1

Maclaurin series for the exponential function

$$e^{x} = \sum_{n=0}^{\infty} \frac{x^{n}}{n!}$$

So to be able to sum this up you have to have $x$ dimensionless.