Hello, I have a question concerning PDEs with boundary conditions. Now, I am trying to solve this PDE to get final expression.

> PDE := diff(c(x,y),x,y)+A*diff(c(x,y),x)+B*diff(c(x,y),y)+C*c(x,y)+D (A,B,C,D are constants)

the boundary condition are

> BC1 := c(0,y)=39;

> BC2 := c(x,0)=39*e^(-x);