@Markiyan Hirnyk i insert with(PDETools) at the first of page

@Markiyan Hirnyk 

thanks for your answer but it doesn’t work

I use your suggested way for simple equation but it responds wrong

I try to get

so I enter in maple

> F := proc (x, y) options operator, arrow; diff(u(x, y), x) end proc;

> tr := {x = h(r, s), y = g(r, s)};

> dchange(tr, F(x, y), [r, s]);

but it answers:

that is obviously incorrect .

please if u have another suggest say . I think and search  two week about this