Exercise 3. Suppose M is a surface in R, and U, V are vector fields on M so that at each p M, U(p) and V(p) are linearly independent. Let 1 and 2 be two 2-forms so that (U, V) 32 (U, V) Show that = 312 as 2-forms. Do not use the lemma: prove directly that m(xp, yp) 312(xp: Yp) for all xp, yp TM. =