Problem 3.1 Reversing the argument given in the discussion of Sec. 2.3 and defining the unit vector n parallel to ? x C, show that dC1 = Qdt| Cin = 1 x Cdt (3.4)Problem 3.2 Show that the average (3.22) over time interval T for f (t) = sin (nut) or f(t) = cos (nwt) for any positive integer n is zero when a) T = 2mm/w for any positive integer m (or T = mm /w for even n) or when the following limit is taken b ) T > > 2 7/ W T = dt f (t) (3.22) o