How to write Latex symbol belongs to : \in means “is an element of”, “a member of” or “belongs to”.

How to write Latex symbol belongs to ?

Latex symbol belongs to or is an element of: \in

$$x \in A$$

which gives:

\[x \in A\]

Examples

Here are few examples.

$$\forall x \in ]-\infty,\infty[$$
\[\forall x \in ]-\infty,\infty[\] 
$$\forall x \in \mathbb{R}$$
\[\forall x \in \mathbb{R}\]