| 
 
 
| Question 1006581:  Q∨P
 R→~P
 R→Q
 Here is what I put but I have not been able to pass correctly.  Feedback is the proof solution is wrong.  Any help would be great.
 Solution
 1) Q∨P
 2) R→~P
 3) Q (SIMP 1)
 4) P (SIMP 2)
 5) R (MP 2, 4)
 6) R→Q (HS 3, 5)
 Simplifying 1, we derive lines 3 and 4. Line 5 comes about as a natural deduction of line 2 and 4. Using DS rule, we derive line 6 from line 3 and 5.
 
 Answer by jim_thompson5910(35256)
      (Show Source): 
You can put this solution on YOUR website! Simplification only works if you have a conjunction. NOT a disjunction. 
 Here is how to do the derivation
 
 1) Q v P (given premise)
 2) R -> ~P (given premise)
 :. R -> Q (what we want to derive)
 ----------------------------------
 3) P v Q (1, commutation)
 4) ~~P v Q (3, double negation)
 5) ~P -> Q (4, Material Implication)
 6) R -> Q (2,5, hypothetical syllogism)
 
 
 | 
  
 | 
 |