Questions on Logic: Proofs answered by real tutors!

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Question 969536: Premises:
1.) V->H
2.) ~V->S
3.) ~H -> ~S
Conclusion:
/H
Click here to see answer by Edwin McCravy(20055)

Question 969535: Premises:
1.) S->~(N v R)
2.) R v N v O
3.) ~O
Conclusion:
/~S
Click here to see answer by Edwin McCravy(20055)

Question 970127: Some things are caused to exist.
Anything caused to exist is caused by another [Nothing can bring itself into existence].
If some things are caused to exist and anything caused to exist is caused by another, then
either there�s a uncaused first cause or there�s an infinite series of past causes.
There�s no infinite series of past causes.
There�s an uncaused first cause.

Click here to see answer by Alan3354(69443)

Question 970141: INSTRUCTIONS: Use natural deduction to derive the conclusion in the following problems.
Use an ordinary proof (not conditional or indirect proof):
1. A ⊃ (Q ∨ R)
2. (R � Q) ⊃ B
3. A � ∼B / R ≡ ∼Q
Click here to see answer by AnlytcPhil(1806)

Question 971097: A -> (B & C)
C -> (E -> I)
~(D -> I) / therefore, (A & G) -> (~I & ~E)
Click here to see answer by Edwin McCravy(20055)

Question 971096: A -> D
~C -> ~D
(C v D) -> ~C / therefore, A -> E
Click here to see answer by Edwin McCravy(20055)

Question 973154: 1. P v R
2. R -> Q ////// :. (P v Q)

Click here to see answer by solver91311(24713)

Question 973506: I need help proving that A V ~~B is a consequence of A V B.
Click here to see answer by Edwin McCravy(20055)

Question 973430: 1. ~(~E.~N)>T
2. G>(N+E) /G>T
Use the eighteen inference rules to construct proofs for the following valid argument
Click here to see answer by Edwin McCravy(20055)

Question 973427: 1. (O+M)>S
2. ~S /~M
Use the eighteen inference rules to construct proofs for the following valid argument
Click here to see answer by Edwin McCravy(20055)

Question 973426: 1. R>~B
2. D+R
3. B /D
Use the eighteen inference rules to construct proofs for the following valid argument
Click here to see answer by Edwin McCravy(20055)

Question 973424: 1. J+(K.L)
2. ~K /J
Use the eighteen inference rules to construct proofs for the following valid argument
Click here to see answer by Edwin McCravy(20055)

Question 974258: If 2.131313...... is written as p/q, such that p and q are positive integers without any common factor, find value of p+q.
Click here to see answer by stanbon(75887)

Question 974259: P(x) is a polynomial such that: P(x + 3/2)=P(x)
If P(17) = 687, find the value of P(23).
Click here to see answer by KMST(5328)

Question 974769: There is a sequence of numbers a1, a2, ... where a1 = 2, a2 = 3, and an = (an-1)/(an-2) for n> 3. What is the value of a1485?
Click here to see answer by solver91311(24713)

Question 974893: Prove:the sum of the squares of two odd integers cannot be a perfect square, i.e, if x and y are both odd, then there is no perfect square z^2 such that x^2+y^2=z^2.
Click here to see answer by amarjeeth123(569)

Question 974899: Prove: The sum of the cubes of two consecutive positive numbers is odd.
Click here to see answer by solver91311(24713)

Question 976349: INSTRUCTIONS: Select the conclusion that follows in a single step from the given premises.
Given the following premises:
1. ∼D ∨ ∼T
2. D ∨ (∼T � ∼R)
3. D

A. (D ∨ ∼T) � (D ∨ ∼R) 2, Dist

B. (D ∨ ∼T) � R 2, Assoc

C. D ∨ T 1, DN

D. ∼T 1, 3, DS

E. ∼T � ∼R 2, 3, DS
What is the answer? I believe it is A...can somebody clarify?
Click here to see answer by jim_thompson5910(35256)

Question 976458: The sum of 2 rational no.is -3..if one no.is - 29/3 then what is other no
Click here to see answer by Tatiana_Stebko(1539)

Question 977619: 1. ~A
2. (C v A) > L
3. A v D
4. (D v U) > C /therefore L

Click here to see answer by jim_thompson5910(35256)

Question 978475: I need help in constructing proofs for this problem. Thank you.
R & (R→S), P & (P→T)├ S & T
Click here to see answer by Edwin McCravy(20055)

Question 976817: give a proof of ⊢ A V B ≡ A V �B ≡ A

Click here to see answer by Edwin McCravy(20055)

Question 978483: logic proofs
E&F,(E → G)&(F→H)├ G&H
Click here to see answer by Edwin McCravy(20055)

Question 978478: What are the proofs?
(A → B) & (A → C) ├ A→ (B & C)
Click here to see answer by Edwin McCravy(20055)

Question 978498: I need help with proofs. Thank you!
D →(B→C), B & −C ├ −D
Click here to see answer by jim_thompson5910(35256)

Question 978496: D→(B→C), B & −C ├ −D
Click here to see answer by Edwin McCravy(20055)

Question 978838: how to prove x ≤ |x|
Click here to see answer by Fombitz(32388)

Question 978864: 1)
2)
3)
4)
5)

Click here to see answer by richwmiller(17219)

Question 979169: Construct a proof in Natural Deduction for the following argument. Show the proof. Do not use the Conditional Proof method.
1. (D -> K) & (J -> K)
2. D v (J & M)
3. (K -> ~A) / (A -> S)
Click here to see answer by jim_thompson5910(35256)

Question 979378: R & (R->S), P & (P->T) |- S & T
Click here to see answer by Edwin McCravy(20055)

Question 979780: 1. (J > O) > ~N
2. N v [~N > (E > N)]
3. ~E > [E v (N v ~O)]
4. J > U
Conclusion: ~O
Can anybody please finish this proof for me? I'm lost.
Click here to see answer by Edwin McCravy(20055)

Question 979778: Can somebody complete the proof for me? I'm having trouble deriving it...
1. (R > O) > ~O
2. B > O
3. R > B
Conclusion: ~B
Help please.

Click here to see answer by Edwin McCravy(20055)

Question 979812: Doing logic problems and I got this one and I just blanked.
1. ~X > C
2. ~J > [(~Q >C) > (~J>~C)]
3. ~Q > ~X
4. ~J
Conclusion: ~~Q
The 2nd line is confusing me on where to go...
Click here to see answer by jim_thompson5910(35256)

Question 979811: Hi all, I have started this proof and got a bit lost...
1. ~H > (~C >W)
2. W v ~H
3. (C <> ~L) > ~C
4. ~W
Conclusion: ~(C <> ~L)
What are the next steps to prove my conclusion?

Click here to see answer by jim_thompson5910(35256)

Question 979816: Hey guys, quick question. How do I work to prove this conclusion?
1. (L > I) > (D>A)
2. (L>D) > (D>I)
3. (L>A) > ~(I & A)
4. L>D
Conclusion: ~(I&A)
Any help would be appreciated!
Click here to see answer by jim_thompson5910(35256)

Question 980047: Hi, I was only given the assumption of ~B and then told to construct a proof with the conclusion of ~(A&B), and I was wondering if you could help me solve this?
Thanks
Click here to see answer by jim_thompson5910(35256)

Question 980134: What is the truth table for this? Is this valid or invalid? Thank you for your help!
S→M, R→M, R ├ S
Click here to see answer by jim_thompson5910(35256)

Question 980136: I need to make a truth table for this. Is this argument valid or invalid?
[Nv-(NvP)]→-R, P ├ R
Click here to see answer by jim_thompson5910(35256)

Question 980137: What is the truth table for this argument? Is this argument valid or invalid?
Thank you for helping me!!
Rv-R, R→(F&S), -R→-(F v S) ├ -(F&-S)

Click here to see answer by jim_thompson5910(35256)

Question 980260: Is this argument valid or invalid? Can you help me construct a truth table? Thank you for your help!
T v P, P ├ -T
Click here to see answer by jim_thompson5910(35256)

Question 980294: Very lost, can somebody please help me finish this proof?
1. (N > K) & (S > L)
2.(N > O) &(G > N)
3. (O > N) & (R > G)
4. O v R
5. ~N
/ K v L
What I have so far...
6. N > K Simp. line 1
7. N > O Simp. line 2
8. O > N Simp. line 3
9. N v G CD line 3 and 4
10. G DS line 5 and 9
I'm extremely lost...can anybody guide me in the right direction?
Click here to see answer by jim_thompson5910(35256)

Question 980258: Is this argument valid or invalid? Can you help me construct a truth table? Thank you!
P↔W, -(P&W) ├ -(P v W)
Click here to see answer by jim_thompson5910(35256)

Question 980633: (~KvN)>Y
Jv(~K&X)
~J
/Y
Click here to see answer by Edwin McCravy(20055)

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