Finding total differential u = x ^ y ^ Z

Finding total differential u = x ^ y ^ Z

u=x^(y^z),lnu=y^zlnx
Find the derivative of X: (&; U / &; x) / u = y ^ Z / X &; U / &; X = uy ^ Z / X
The derivative of Y is: (&; U / &; y) / u = ZY ^ (Z-1) LNX &; U / &; y = uzy ^ (Z-1) LNX
Find the derivative of Z: (&; U / &; Z) / u = y ^ zlnylnx &; U / &; Z = uy ^ zlnylnx
dz=u(y^z/x dx+zy^(z-1)lnx dy+y^zlnylnx dz)