Formula_16583

\[\iint_{S}\left|\begin{array}{ccc}\cos \alpha & \cos \beta & \cos \gamma \\\frac{\partial}{\partial x} & \frac{\partial}{\partial y} & \frac{\partial}{\partial z} \\P & Q & R\end{array}\right| d S=\int_{\partial S} P d x+Q d y+R d z .\]