Finding differentials and solve in terms of other differentials

[arne.niebel]

Hi, does someone have an idea how to approach this question? Help would really be appreciated!

 

[blamocur]

You have 2 equations with 2 variables. Differentiating each of them over 'x' and 'y' will give you 4 equations with form variables $\frac{\partial u}{\partial x}$, $\frac{\partial u}{\partial y}$, $\frac{\partial v}{\partial x}$ and $\frac{\partial v}{\partial y}$