1. The problem statement, all variables and given/known data ~(X&Y) } ~X v ~Y I need to be able prove this rule, also known as Demorgan's rule. Preferably by using any of the following rules: MP, MT, CP, DN, &E, &I, DS <>I, <>E, vI. Although basically any rules that don't go way over my head and aren't way too advanced for me I could use as well. As long as I am able to understand it. I might be able to get away using RA (reductio ad absurdum) but I am not sure and I don't think I am supposed to be using it in this proof, so I want to stay away from using that. 2. Relevant equations All the relevant info about the problem is given above. It's a proof of Demorgan's rule (or at least one of them I guess). 3. The attempt at a solution ~(X&Y) } ~X v ~Y 1 1. ~(X&Y) A I am not really sure where to start. I need to know how to do this in order to take an upcoming exam and I am totally lost right now. If someone could either provide an answer or help me out on this I would greatly appreciate it. Thanks!