Question 912745: 1. Q horseshoe R
2. ~P
3. P v Q /R
4. 2,3,DS
5. 1,4,MP
the question is what fits in 4 and 5 i know 5 is R but cannot seem to figure out what 4 is. Thank you for your help!!
Answer by jim_thompson5910(35256)   (Show Source):
You can put this solution on YOUR website! DS stands for "Disjunctive Syllogism"
The rule is
P v Q
~P
therefore, Q
It's a fancy way of saying: "you have two options, but one of those options is taken away from you: so you're just left with one option"
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Line 3 has a disjunction which is P v Q. Line 2 has the negation of P, so that forces Q to be leftover
Therefore, Q must go in line 4. Line 5 is definitely R because that's the overall conclusion you want to get to.
Let me know if you need more help or if you need me to explain a step in more detail.
Feel free to email me at jim_thompson5910@hotmail.com
or you can visit my website here: http://www.freewebs.com/jimthompson5910/home.html
Thanks,
Jim
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