For HW 1, Question 2, when doing the inductive step, you want to have "easy" algebra to work with. For this reason, you will want to keep the Phi and phi values out of the denominator. If you find that you have several places where Phi and/or phi are raised to power and you want to simplify by dividing something out, choose the SMALLEST power and divide out using that so that Phi and/or phi do not end up in the denominator.