Eliminate Vertical Space in $$ $$

Question

Im having problems with the vertical space that the $$ $$ command creates. For example:

\begin{multicols}{2}
\begin{enumerate}
\item  \[\sum\limits_{k=1}^{\infty}\frac{k^2e^{-2k}}{k^2+1}\]
\item $$\sum\limits_{k=1}^{\infty}\frac{\left|\sin{k^4}\right|}{\sqrt{k^4+1}}$$
\end{enumerate}
\end{multicols}

This creates a vertical space between the \item and the object in the $$ $$ command. I just want to eliminate this effect. One possible solution is to use the fast math mode: $object$. But, this doesn't satisfy me.

Answer 1

First of all you should not use $$ ... $$ in LaTeX but \[ ... \]. Then: you are asking for display-math which is centered. This causes the vertical space. You need inline math, i.e. use $ ... $ or \( ... \) instead. You can add \displaystyle at the beginning to get the same style used as before:

\item $\displaystyle\sum\limits_{k=1}^{\infty}\frac{\left|\sin{k^4}\right|}{\sqrt{k^4+1}}$