Calculate Euler's number by limit-function

[Maro]

When calculating the following limit in CAS mode

\( \lim_{x \rightarrow \infty}(1+\frac{1}{x})^x = e = 2.71828...\)

the Prime gives "1" as result (which is wrong) instead of the Euler's number. When doing the same with the 50g there is no problem.

Any idea?