SOLUTION: 1. Q horseshoe R 2. ~P 3. P v Q /R 4. 2,3,DS 5. 1,4,MP the question is what f

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"

--------------------------------------------------------------

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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