limit in latex code example

Example 1: how to do limits in latex

$\lim_{x \to +\infty} f(x)$

Example 2: itemize latex

\begin{enumerate}
  \item The labels consists of sequential numbers.
  \item The numbers starts at 1 with every call to the enumerate environment.
\end{enumerate}

Example 3: limit in latex

$\lim_{x\to\infty} f(x)$

Example 4: integral latex

$\int_0^{2a}{\cos(x)dx}$