2. (a) Use the Trigonometric Substitution x = 3 sec 0 to evaluate 2x dx. Vx2 - 9 Hint: You will need to use that sec2 0 -1 = tan2 0 and that an antiderivative of sec2 0 is tan 0. (b) What's another method that can be used to evaluate the integral from part (a)? If this method includes choices like u, x, du, etc., specify what choice(s) you would make. (You do not need to evaluate the integral again using this other method.)