5. If u and v be both functions of the same function of x and y, prove that 6. If V=ƒ(u, v), u=fi(x, y), v=f2(x, y), show how to find Ex. Given u = x2 + y2, v = 2xy, show that 12. Prove V2 = m(m + 1),−2. 13. If u and u be functions of x, y, z, both satisfying V2 V = 0, 14. If V, be a homogeneous function of the nth degree, |