Limits in TeX language are described by expression having the following scheme '\lim_{... \to ...} ...' where the first dots is for variable that approaches and the second dots is for the limit of this approaching process, the third dots is for expression itself.

The limit of approaching process can be any expression.

\lim_{x \to 0} (1+x)^{\frac{1}{2}} = e

To check yourself enter the following formula in TeX: