1.) Determine all the pos. int. n such that Phi(n) has the following values. Make sure that you have proved that you found all the soln's.

a.) 1

b.) 2

c.) 3

d.) 4

2.) Find all pos int. n shut that Phi(n) = 6. Again, make sure you've proven that you found all solutions.

3.) For which integers n (positive) is Phi(n) div. by 4?