Originally Posted by

**JulieK** I have the following equation

$\displaystyle \frac{\partial}{\partial y}\left(m\frac{dy}{dx}\right)=0$

where $\displaystyle y$ is a function of $\displaystyle x$ and $\displaystyle m$ is a function of $\displaystyle y$. If I integrate this equation first with respect to $\displaystyle y$ should I get a function of $\displaystyle x$ as the constant of integration (say $\displaystyle C\left(x\right)$) or it is just a constant? If it is a function, how can I then find its form (e.g. polynomial, etc.)? Should I use boundary conditions or I can decide about the form from inspecting the type of the equation.