b g(b) Use the Substitution Formula, f(g(x)) . g'(x) dx = f(u) du where g(x) = u, to evaluate the following integral. a g(a) O W/ H 3 sin (3t) dt. 6 - cos (3t) . . . 3 sin (3t) 6 - cos (3t) dt = (Type an exact answer.)