jQuery documentation  :eq returns Array <Element> and
eq() returns one jQuery object. What does means "Array <Element>"?
It is a single element? By the other hand eq() => "Reduce the set of
matched elements to a single element." So, both returns a single
element and it seems to me that there isn't any difference between :eq
and eq(). Is one faster than the other? Why are there two sintaxes to
achieve the same task? Or am I missing sometghing?