A question in my ODE textbook is as follows.
Determine whether the given first-order differential equation is linear in the indicated dependent variable.
$u dv+(v+uv-e^u)du = 0;$ in v; in u;
I feel as though I would be able to solve the question if I knew what the in v; in u; means.
In this question, what does in v; in u; mean? Is this a standard notation, and if so, what is it called?