Can some one guide me towards the right answer?thanks.
S be a smooth, orientable surface, with unit normal n and boundary
C. Let C be oriented, with respect to n, as in the statement of Stokesí
Theorem. Let f and g be continuous functions defined on S, with
continuous first and second order partial derivatives.
a)show that ∮(f∇g).dr=∫∫s(∇fx∇g).nds
b)show that ∮(f∇g+g∇f).dr=0