Question 1008772:  1. (R v S) > (H & ~G) 
2. (K v R) > (G v ~H)     /   ~R 
 
 Answer by jim_thompson5910(35256)      (Show Source): 
You can  put this solution on YOUR website! Proof by contradiction
 
 
| Number | Statement | Lines Used | Reason | 
|---|
 | 1 |  | (R v S) -> (H & ~G) |  |  |  | 2 |  | (K v R) -> (G v ~H) |  |  |  | .: |  | ~R |  |  |   | 3 | ~~R |  | AIP |   | 4 | R | 3 | DN |   | 5 | R v S | 4 | Add |   | 6 | R v K | 4 | Add |   | 7 | K v R | 6 | Comm |   | 8 | H & ~G | 1,5 | MP |   | 9 | ~G & H | 8 | Comm |   | 10 | H | 8 | Simp |   | 11 | ~G | 9 | Simp |   | 12 | G v ~H | 2,7 | MP |   | 13 | ~H | 12,11 | DS |   | 14 | H & ~H | 10,13 | Conj |  | 15 |  | ~(~~R) | 3-14 | IP |  | 16 |  | ~R | 15 | DN |  
 
 
 
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Acronyms/Abbreviations Used
 
 
Add = Addition 
AIP = Assumption for Indirect Proof 
Comm = Commutation 
Conj = Conjunction 
DM = De Morgan's Law 
DN = Double Negation 
DS = Disjunctive Syllogism 
IP = Indirect Proof (aka proof by contradiction) 
MP = Modus Ponens 
Simp = Simplification 
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