Dear all,

If u is the function of x,y,z and w, that is, u = u(x,y,z,w). Then the partial derivatives of u with respect to x, y, and z are dx(u), dy(u), and dz(u). But how do we define the partial derivative of u with respect to w?

If u is the function of x,y,z and w, that is, u = u(x,y,z,w). Then the partial derivatives of u with respect to x, y, and z are dx(u), dy(u), and dz(u). But how do we define the partial derivative of u with respect to w?