Hello everyone!

I have a question about primitive roots. I'm just trying to come up with general strategies that would help we remember tricks on how to find all primitive roots. So I came up with a few basic cases and perhaps one of you could explain how to solve them. Here it goes:

Find all primitive roots for:

i) 13

ii) 2 * 13

iii) 13^2

iv) 2 * 13^4

Thanks again for your help. I appreciate it. Happy Easter.