I see intuitively $\left( 1+\dfrac {1} {n}\right) ^{n}$ is increasing but I think, it is not obvious. How can I prove this?
Recall. If sequence of $\left\{ x_{n}\right\} _{n}$ is increasing then $x_n<x_{n+1}$ for all $n\in\mathbb{N}$.
Note that the limit converges to $e$ (Euler's number).