Questions on Logic: Proofs answered by real tutors!

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Question 1034192: [(N+O)>P]
[(P+Q)>R]
(Q+N)
~Q
/R

Click here to see answer by Edwin McCravy(20054) About Me 

Question 1034245: Hello I stuck on this question can you please help?
INSTRUCTIONS: Use natural deduction to derive the conclusion in the following problems.
Use conditional proof:
1. N ⊃ (F • A)
2. B ⊃ (R • F) / (N ∨ B) ⊃ (A ∨ R)

Click here to see answer by Edwin McCravy(20054) About Me 

Question 1035225: 3.(S v T) v (U v W), therefore, (U v T) v (S v W)
Click here to see answer by Edwin McCravy(20054) About Me 

Question 1035372: 1. S.R
2. S>X
3. X>~R /:. (X.S).(~RvW)

Click here to see answer by solver91311(24713) About Me 

Question 1035834: Let x and y be vectors in R^4 with {x,y} being linearly independent. Prove that there exists a non zero vector z that is orthogonal to both x and y.
Thanks!

Click here to see answer by richard1234(7193) About Me 

Question 1038288: (X^Y)v(T^R)/~~(RvY)
Click here to see answer by Edwin McCravy(20054) About Me 

Question 1038285: ~R>P
(~P^S)^Z/R^S

Click here to see answer by Edwin McCravy(20054) About Me 

Question 1038546: 1). AvB
2). C
3). (A^C)>D
4). ~(~F^B)/DvF
I have been working on this for hours. Can someone please help me?

Click here to see answer by jim_thompson5910(35256) About Me 

Question 1038664: I have bee having trouble solving these problems and been at it for hours I need help. Anyone's help would be greatly appreciated. I have to prove them.
Problem #1
1) (B^A)->D
2)A
3) C->~D/~(C^B)
4) :. (C^B)
Problem #2
1) (D^S)^T
2) [(Sv~F)vZ]->C/C^T
3) :. C^T
Problem #3
1) A->B
2) D->E
3) ~(B^E)/ ~Dv~A
4) :. ~Dv~A
Problem #4
1)~[(A^B) v (Cv~R)]
2) (T^~S)-> (Cv~R)
3) ~S/~T
4) ~T
Problem #5
1) (~Z^W)->Q
2) ~Z
3) R<-> (W^~Q)/~R
4) ~R

Click here to see answer by solver91311(24713) About Me 

Question 1038513: Solve the problem using rules of inference and replacement:
Premise 1) Q v (R . S)
Premise 2) (Q > T) . (T > S)
Conclusion /:S

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Question 1038900: What is the similarity between 85,17,19,4 and 2?
Click here to see answer by ikleyn(52775) About Me 

Question 1039101: Hello, I need help with this Statement/Reasons type question.
Complete the following solution by filling in the missing statements and reasons.
•Statement: x-2(3x-4)=8 Reason:Given
•Statement:_________ Reason:Distributive Property
•Statement:-5x+8=18 Reason:Simplify
•Statement:_________ Reason:____________
•Statement: x=-2 Reason:____________
Thank you so much (:

Click here to see answer by jim_thompson5910(35256) About Me 

Question 1039399: I need help annotating this proof because I really dont understand.
1. ~H ∨ F
2. F → J
3. ~~H ∴ ~F ∨ J
4. F
5. J
6. ~F ∨ J

Click here to see answer by Edwin McCravy(20054) About Me 

Question 1039719: Two column proof for:
(p^q)^(~qvr)^(~rvs)=>s
Need step and reasoning

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Question 1040844: 512 64 16 8 8 16 ?

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Question 1040844: 512 64 16 8 8 16 ?

Click here to see answer by Alan3354(69443) About Me 

Question 1041010: 1 3 10 37 ?

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Question 1041047: Note that ‘->’ is used for conditionals, ‘~’ is used for negations, ‘v’ is used for disjunctions, ‘&’ is used for conjunctions, ‘<->’ is used for biconditionals, and ‘/’ is used as the conclusion indicator.
Prove the following three arguments to be valid using the method of Natural Deduction. Do not use Conditional Proof in these proofs.
1. ~(P v Q)
2. (R v S) -> P / ~S

1. P v (Q v R)
2. (~T & ~R) / (Q v P)

1. (P v Q) -> R
2. (S v R) -> T
3. ~(Q -> E) / T

Click here to see answer by robertb(5830) About Me 

Question 1041143: Solve the following proof using the methods of natural deduction, as you did in the HW problems in Chapter 7. There may be many ways to solve the proof. You get partial credit for correct use of rules, even if you don't finish the proof. Incorrect use of rules with be penalized.
Good luck,

For the horseshoe use the > sign
For the Triple bar use the = sign
For the and use the . sign
For the or use the v sign
For negation use the - sign
1. (G . H) v (M . G)
2. G > (T . A) / A

Click here to see answer by solver91311(24713) About Me 

Question 1041461: Hello, can you please help me with this problem?
Use one of the indirect proof techniques (reductio ad absurdum or conditional proof) to demonstrate the validity of the argument.
~S → (F → L), F → (L → P), therefore, ~S → (F → P)

Click here to see answer by jim_thompson5910(35256) About Me 

Question 1041745: P•Q R
Click here to see answer by Alan3354(69443) About Me 

Question 1042178: I have been super stuck on a logic puzzle and I need help! I have to translate it into symbolic form then use the rules, implication rules and replacement rules, along with indirect proof to derive the conclusion.
Here is the puzzle with the letters for the simple statements provided:
If the murder happened in the hotel room, then there are bloodstains somewhere in the room. It follows that it is not the case that the murder happened in the hotel room and there are not bloodstains somewhere in the room. (M, B).

Click here to see answer by solver91311(24713) About Me 

Question 1042390: (PvQ)&R
(R&P)>S
(Q&R)>S
Therefore,
S

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Question 1042390: (PvQ)&R
(R&P)>S
(Q&R)>S
Therefore,
S

Click here to see answer by Edwin McCravy(20054) About Me 
Question 1042390: (PvQ)&R
(R&P)>S
(Q&R)>S
Therefore,
S

Click here to see answer by robertb(5830) About Me 

Question 1042389: PvQ
(QvU)>(P>T)
~P
(~PvR)>(Q>S)
Therefore,
TvS

Click here to see answer by jim_thompson5910(35256) About Me 

Question 1042510: 1. (⌐SvL)→F, ⌐[P v (QvS)] Ⱶ F
2. ⱵS → (B→S)



Click here to see answer by robertb(5830) About Me 

Question 1042741: I'm confused on how to do these proofs. Would appreciate it if someone helped me.
https://gyazo.com/48d4c41ac13022fdd5ff3b3478e89c7f
Thanks!

Click here to see answer by ikleyn(52775) About Me 

Question 1042846: Prove by mathematical induction,1^2+3^2+....(2n+1)^2=((n+1)(2n+1)(2n+3))/3 where 'n' is a positive integer?

Click here to see answer by ikleyn(52775) About Me 

Question 1042855: Let a, b ∈ R. Prove using contradiction that if a ∈ Q and ab ∉ Q then b ∉ Q.
Click here to see answer by ikleyn(52775) About Me 

Question 1042857: a, b, n ∈ Z with n > 1. Prove that if a ≡ b (mod n) then 2a ≡ 2b (mod n).
Click here to see answer by rothauserc(4718) About Me 

Question 1042733: (RvS) > (H & ~G)
(k v r) > (G v ~H)
/~R
question2
n>r
o<>r
(o>r)>L
/(n>o)&L

Click here to see answer by solver91311(24713) About Me 

Question 1042856: Let a, b, n ∈ Z with n > 1. Prove that if a ≡ b (mod n) then 2a ≡ 2b (mod n)

Click here to see answer by jim_thompson5910(35256) About Me 

Question 1042957: Let a, b, n ∈ N with n ≥ 2. If a^3 ≡ b^3 (mod n) then a ≡ b (mod n)
I think I have found a counterexample where a = 2 b = -4 and n = 4
is this valid?

Click here to see answer by richard1234(7193) About Me 

Question 1042956: If x, y ∈ Q then there are integers a, b, c such that x = a/c and y =b/c
Can this be proven using a proof or is there a solid counterexample?
.

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Question 1042996: prove, if x,y ∈ Q
then there are integers a,b,c
such that x=a/c and y=b/c

Click here to see answer by LinnW(1048) About Me 

Question 1042995: Prove that, if d is a factor of x,and d is also a factor of y
where d>=1,x>=1,y>=1 ∈ Z
then d^2 is a factor of x multiplied by y

Click here to see answer by ikleyn(52775) About Me 
Question 1042995: Prove that, if d is a factor of x,and d is also a factor of y
where d>=1,x>=1,y>=1 ∈ Z
then d^2 is a factor of x multiplied by y

Click here to see answer by LinnW(1048) About Me 

Question 1043036: 1^2+3^2+5^2+.....+n^2. What kind of series it is?



Click here to see answer by ikleyn(52775) About Me 

Question 1043570: Proof by Natural Deduction – Propositional Logic. Use a direct proof to show that the following argument is valid.

Premise 1: (E • I) v (M •U)
Premise 2: ~E
Conclusion: ~(E v ~M)

Click here to see answer by robertb(5830) About Me 

Question 1044057: Hi
Can anyone help me with this problem, really struggling on where to start.
If C ⊆ A ∩ B then C ⊆ A and C ⊆ B.
Thanks

Click here to see answer by robertb(5830) About Me 

Question 1044054: Can anyone help me with this, I don't really understand how to set up the proof
If C ⊆ A ∩ B then C ⊆ A and C ⊆ B.
Thanks

Click here to see answer by jim_thompson5910(35256) About Me 

Question 1044147: Can anyone tell me if I'm on the right track with this:
Question:
Let G = (V, E) be a directed graph. Let u, v ∈ V be distinct vertices. Define C(u) to be a
strongly connected component of G that contains u, and C(v) a strongly connected component
of G that contains v. Prove that either C(u) and C(v) do not share any vertex or C(u) and
C(v) are equal. [5 marks]
[Hint: To write such a proof you can begin with: “If C(u) and C(v) do not share any vertex
then the result is true, so suppose C(u) and C(v) share a vertex.”]
My answer:
A directed graph is strongly connected if there is a path from a to b, and a path from b to a, whenever a and b are vertices in the graph.
therefore if C(u) and c(V) share a vertex say w,
for the graph to be directed there must be strongly connected components between C(u) and C(w), and strongly connected components between C(v) and C(w)
Therefore as C(u) is strongly connected to C(w) and C(v) is strongly connected to C(w) (we have previously proved this theorem u,v,w E G(V,E) so c(u) is strongly connected to C(v) so therefore as they are both strongly connected to w in order for the definition to hold they must be equal and part of the same graph

Click here to see answer by richard1234(7193) About Me 

Question 1045062: Hello there i need help with this question.
using 8 rules of implication and 10 rules of replacement.Regular proof.
1.A>~B
2.BvD
3.~Dv-c
4.E>C/A>~E

Click here to see answer by robertb(5830) About Me 

Question 1045414: Please help me answer this one natural proof CORRECTLY using the 8 rules of implication and 10 rules of replacement, thank you! 1. (Q•R)v(~Q•~R) 2. N>~(Q=R) 3. EvN / E
Click here to see answer by robertb(5830) About Me