\begin{saveblock}{align}
    \begin{highlightblock}[gobble=12,linewidth=\textwidth,
        framexleftmargin=0.25em,xleftmargin=0.25em]
        De verdubbelingsformule herschrijven we nu als
        \begin{align}
            \cos(2\theta) &= \cos^2(\theta) - \sin^2(\theta)
            \nonumber\\
            &= 2\cos^2(\theta)-1.
        \end{align}
    \end{highlightblock}
\end{saveblock}

\begin{saveblock}{alignEN}
    \begin{highlightblock}[gobble=12,linewidth=\textwidth,
        framexleftmargin=0.25em,xleftmargin=0.25em]
        The double-angle formula can now be rewritten as
        \begin{align}
            \cos(2\theta) &= \cos^2(\theta) - \sin^2(\theta)
            \nonumber\\
            &= 2\cos^2(\theta)-1.
        \end{align}
    \end{highlightblock}
\end{saveblock}

\addtorecentlist{\textbackslash nonumber}

\begin{frame}{Align}
    \useblock{align\langsuffix}

    \includegraphics[width=\linewidth,height=0.4\textheight,keepaspectratio]{%
        assets/mathAlignSecondNumbered\langsuffix.pdf}
\end{frame}