# pdes

1. ### Multi-variable PDEs

PDEs Solve the equations below : (a) \partial z(x,y) =x^{-1} +y^{-1} . (b) \partial_{x} \partial _{y} Z(x,y)=xy+x+1.
2. ### Classifying PDEs as elliptic, parabolic and hyperbolic help

Hi, I need to show whether the first-order wave equation du/dt + (c * du/dx) = 0 is elliptic, hyperbolic or parabolic. But I've not seen a method for 1st-order PDEs. The 'd' are really for partial differential derivatives but I don't know how to insert the right character here. My textbook...