(x^4 + y^4 )^1/2 = x^2 + y so i do take the derviative of both sides. and i get 1/2 ( x^ 4 + y^4) ^-1/2 ( 4x^3 + 4y^3(dy/dx) = 2x + dy/dx However i am stuck and can not isolate for dy/dx can some1 help me thanks