# Something off with \pause in beamer

Something is off with \pause in my beamer file below. It does not work properly. Any idea why?

% !TEX encoding = UTF-8 Unicode
\documentclass{beamer}

\begin{document}

\begin{frame}[shrink=10]

\begin{align}
P(Y_i=1) = & \begin{pmatrix}
n_i \\
y_i \\
\end{pmatrix}\pi_i^{y_i}(1-\pi_i)^{n_i-y_i}  \\ \pause
\mathcal{L} (\boldsymbol{\beta|y}) = & \prod_{i=1}^N
\begin{pmatrix}
n_i \\
y_i \\
\end{pmatrix}\pi_i^{y_i}(1-\pi_i)^{n_i-y_i} \\ \pause
= & \prod_{i=1}^N
\begin{pmatrix}
n_i \\
y_i \\
\end{pmatrix}\Big (\frac{\pi_i}{1-\pi_i} \Big)^{y_i}(1-\pi_i)^{n_i} \\  \pause
\log{\mathcal{L} (\boldsymbol{\beta|y}) } = & \sum_{i=1}^N \Bigg[y_i \log{\Big     (\frac{\pi_i}{1-\pi_i}\Big )} + n_i \log{(1-\pi_i)} + \log \begin{pmatrix}
n_i \\
y_i \\
\end{pmatrix} \Bigg ]
\end{align}

\end{frame}

\end{document}

• Section 23.4 of the manual; align doesn't cooperate well with \pause. – egreg Nov 29 '14 at 18:26
• The code above perfectly works on Mac, but not on windows. Any idea how to fix this? – Günal Nov 29 '14 at 18:28
• Sorry, but Windows and I don't get along well. – egreg Nov 29 '14 at 18:33
• Neither do I :) – Günal Nov 29 '14 at 18:36

Uncovering a displayed multiline numbered formula in beamer is a little tricky, as explained in Section 23.4 Uncovering Tagged Formulas Piecewise of the beamer manual; there, you can also find the recommended approach: to use \uncover and an empty last line afterwards compensated using a negative vertical space:

% !TEX encoding = UTF-8 Unicode
\documentclass{beamer}

\begin{document}

\begin{frame}[shrink=10]

\begin{align}
\uncover<+->{
P(Y_i=1) &=  \binom{n_i}{y_i}\pi_i^{y_i}(1-\pi_i)^{n_i-y_i}  \\
}
\uncover<+->{
\mathcal{L} (\boldsymbol{\beta\mid y}) &=  \prod_{i=1}^N
\binom{n_i}{y_i} \\
}
\uncover<+->{
\pi_i^{y_i}(1-\pi_i)^{n_i-y_i}
&= \prod_{i=1}^N
\binom{n_i}{y_i}\Bigl(\frac{\pi_i}{1-\pi_i} \Bigr)^{y_i}(1-\pi_i)^{n_i} \\
}
\uncover<+->{
\log{\mathcal{L} (\boldsymbol{\beta|y}) } &= \sum_{i=1}^N
\Biggl[y_i \log{\Bigl(\frac{\pi_i}{1-\pi_i}\Bigr)}
+ n_i \log{(1-\pi_i)} + \log \binom{n_i}{y_i}\Biggr] \\
}
\notag
\end{align}
\vskip-1.5em

\end{frame}

\end{document}


An animation of the result:

Not related to the question, but I made some other modifications to your code: to use \binom instead of bmatrix and to use the "lateral" versions \Biggl, \Biggr instead of just \Bigg to guarantee proper space handling.