Display & Inline Math

Another day in latex wonderland … Today I was writing an equation in an aligned environment using sum and those fancy things. Unfortunately aligned is a display math environment such that the limits of sum are displayed above and below, which was really not suitable in my case. So how do I display inline-math style in a display math environment?

Let’s say we have an equation environment with an equation

\begin{equation*}
    \sum_{i=0}^{n} x^i
\end{equation*}

To display the sum as inline math we can simply use \textstyle.

\begin{equation*}
    {\textstyle \sum_{i=0}^{n} 2^i} \prod_{i=0}^{n} i^2
\end{equation*}

Note that the prod is display math again.