If `U(x,y,z) = log(x^(3) + y^(3) +z^(3))` find `(del U)/(dx) + (del U)/(dy) + (del U)/(dz)`

If U(x,y,z) =(x^(2) + y^(2))/(xy) + 3z^(2)y , find (del U)/(dx) + (del U)/(dy) + (del U)/(dz)

If u=log (x^(3) + y^(3) +z^(3) - 3xyz) , then (del u)/(del x) + (del u)/(del y) + (del u)/(del z)=

If v(x,y) = log (e^(x) + e^(y)) , then (del v)/(del x) + (del v)/(del y) is equal to

If w(x,y,z) = log((5x^(3)y^(4) + 7y^(2)xz^(4) - 75y^(3)z^(4))/(x^(2) + y^(2))) , find x(del w)/(del x) + y(del w)/(del y) + z(del w)/(del z) ,

If w(x,y,z) = x^(2)(y-z) + y^(2)(z-x) + z^(2)(x-y) , then (del w)/(del x) + (del w)/(del y) + (del w)/(del z) is

If u = log ((x ^(2) y + y ^(2) x)/(xy)) then x (del u)/( del x) + y (del u)/(del y)=