Out of context it means nothing. A partial derivative means changing the indicated variable while keeping some other variable(s) constant. Usually it is obvious what those other variables are. In a 3D coordinate system partial wrt one coordinate implies keeping the other two constant.What is the result of this kind of partial differentiation?
\begin{equation*}
\frac{\partial}{\partial x} \left(\frac{\partial x}{\partial t}\right)
\end{equation*}
Is it zero?
Thank you in advance.
In that case I assume that partial wrt x means other spatial coordinates are held constant, but what is the significance of the partial wrt to t? What is being held constant there? I.e., why is it not just dx/dt?I apologize for the missing context. For example, ##x## signifies position and ##t## as time.