diff(F(x,F(x)), x);

how to differentiate this?

(D[1](F))(x, F(x))+(D[2](F))(x, F(x))*(diff(F(x), x))

how to find (D[1](F))(x, F(x)) and (D[2](F))(x, F(x)) ?

i guess need define new calculus for two variables

Limit((F(x+h,F(x+h)) - F(x,F(x)))/h, h = 0);

Limit((F(x+h,F(x)) - F(x,F(x)))/h, h = 0);

Limit((F(x,F(x+h)) - F(x,F(x)))/h, h = 0);

Limit((F(x+h,F(x,y)) - F(x,F(x,y)))/h, h = 0);

Limit((F(x,F(x+h,y)) - F(x,F(x,y)))/h, h = 0);

if inside F(x) is F(x,y)

it seems need to find the basic definition of F(x,y) first

if i define F(x,y) as

F := (x,y) -> min(x,y)/max(x,y);

i may be wrong, how to differentiate correctly?