Re: \bigl \bigr

Eccola! 🙂
`
\begin{equation}
\frac{\partial \phi}{\partial t} = \lambda \frac{\partial}{\partial z} \bigl{ k (1-\phi) – \frac{\partial p_e}{\partial z} – (1- \phi) \bigr };
\end{equation}
`
Grazie!