Questions on Logic: Proofs answered by real tutors!

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Logic: Proofs

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Question 189540: 3) I can only use the 8 rules of inference...
1. (M v N) → ~S
2. T → (M v N)
3. ~S → ~(M v N) / T → ~(M v N)
________________________
4.
5.
6.

Click here to see answer by jim_thompson5910(13794)

Question 189539: 7)I can only use the 8 Rules of Inference. Need help!!!
1. (T → C) → ~F
2. S → C
3. T → S
4. F v ~P /~P
________________________
5.
6.
7.
8.
9.

Click here to see answer by jim_thompson5910(13794)

Question 189538: 2) I can only use the 8 Rules of Inference. I have tried and tried...it just doesn't jive with me...help please!
1. (E v F) → ~G
2. ~H
3. H v K
4. (K v L) → E / ~G
________________________
5.
6.
7.
8.
9.

Click here to see answer by jim_thompson5910(13794)

Question 189335: Prove that

Click here to see answer by Edwin McCravy(2922)

Question 193059: Construct proofs using the Rules of Inference and the Rules of Replacement. The conclusion appears after the slash.
1. ~E
2. F → (D v E)
3. ~D / ~F

Click here to see answer by jim_thompson5910(13794)

Question 193058: Construct proofs using the Rules of Inference and the Rules of Replacement. The conclusion appears after the slash.
1. ~P
2. ~(P v Q) → ~R
3. ~Q / ~R

Click here to see answer by jim_thompson5910(13794)

Question 193057: Construct proofs using the Rules of Inference and the Rules of Replacement. The conclusion appears after the slash.
1. ~(S v R)
2. P → R / ~P

Click here to see answer by jim_thompson5910(13794)

Question 193056: Construct proofs using the Rules of Inference and the Rules of Replacement. The conclusion appears after the slash.
1. (A v B) v C
2. ~A / C v B

Click here to see answer by jim_thompson5910(13794)

Question 193060: Construct proofs using the Rules of Inference and the Rules of Replacement. The conclusion appears after the slash.
1. P • P
2. Q → ~P / ~Q

Click here to see answer by jim_thompson5910(13794)

Question 193062: Construct Conditional Proofs
1. (A v B) → (C • D) / A → C

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Question 193061: Construct Conditional Proofs

1. P → Q
2. (P • Q) → R
3. P → (R → S)
4. (R • S) → T / P → T (Hint: This is a long proof!)

Click here to see answer by jim_thompson5910(13794)

Question 194154: I started with:
(P v ~P)
I have gotten to this point:
~(P v ~P) Assumption
...
(P v ~P)
_|_ (falsum)I 1,2
(P v ~P) ~E 3
I don't know where to go from there? divide and then there is your answer
Click here to see answer by chewyben(1)

Question 194331: Please help me with this problem for proofs:
1. A-> ~(B ->G)
2. A v G / A<-> ~G
I'm thinking there will be some Hypothetical syllogism to find the conclusion. I am really bad at this thought, so I am uncertain. Please help me! I really appreciate it. Thank you!
Click here to see answer by jim_thompson5910(13794)

Question 194330: Please help me solve this problem....
1. J v (I * S)
2. J-> S / S.
I need to find the proof for it and I am horrible at this. I appreciate any kind of help. Thank you!
Click here to see answer by jim_thompson5910(13794)

Question 195915This question is from textbook
: Concerned about Friday absenteeism, management examined absenteeism rates for the last three Fridays in four assembly plants. Does this sample prove that there is a significant difference in treatment means? Absences
Month Plant 1 Plant 2 Plant 3 Plant 4
4-Mar 19 18 27 22
11-Mar 22 20 32 27
18-Mar 20 16 28 26
This question is from textbook

Click here to see answer by stanbon(26291)

Question 196029: I need help finishing this proof.
(P . Q) -> (R v S) :. (P -> R) v (Q -> S)
1. (P . Q) -> (R v S)
Click here to see answer by jim_thompson5910(13794)

Question 196028: I need help finishing this proof.
(P . Q) -> (R v S) :. (P -> R) v (Q -> S)
1. (P . Q) -> (R v S)
Click here to see answer by jim_thompson5910(13794)

Question 196027: I need help finishing this proof.
(A . B) -> (E -> A), (A . B) v C, C -> D :. (E -> A) v D
1. (A . B) -> (E -> A)
2. (A . B) v C
3. C -> D
Click here to see answer by jim_thompson5910(13794)

Question 196024: I need help finishing this proof.
(~K -> K) -> ~L, ~(~L -> ~M) -> L, M :. K <-> ~L
1. (~K -> K) -> ~L
2. ~(~L -> ~M) -> L
3. M
Click here to see answer by jim_thompson5910(13794)

Question 196020: I need help finishing this proof.
A v (~B v ~C), A -> (D -> E), ~(~B v ~D) :. C -> (D -> E)
1. A v (~B v ~C)
2. A -> (D -> E)
3. ~(~B v ~D)
Click here to see answer by jim_thompson5910(13794)

Question 196304: when 63 is added to 1 fifth off my number the result is double my number
Click here to see answer by anantha(74)

Question 196932: Prove or disprove: If two triangles have two pairs of congruent sides, the triangles must be congruent.
Click here to see answer by vleith(1977)

Question 196930: Prove or disprove: any two right triangles with the same
length hypotenuse have the same area.
Click here to see answer by Edwin McCravy(2922)

Question 198313: Justify each step of the proof.
Conjecture: If 2(x^2+5)=60, then x is 5 or -5.
Could you show me the reason to each step, please?

thank you
Click here to see answer by stanbon(26291)

Question 198437: construct a truth table for ~q -> (~q^p)
Click here to see answer by jim_thompson5910(13794)

Question 198757This question is from textbook a survey of mathematics with apllications
: 3. Write the following compound statement in symbolic form
Let p: Today is Friday.
q: Tomorrow is not the day to go shopping.
If tomorrow is not the day to go shopping, then today is not Friday.

4. Construct a truth table for ~ (p Ù q)

5. Write the converse, inverse, and contrapositive of the following conditional statement
If the sun is shining, then it will not rain.
This question is from textbook a survey of mathematics with apllications

Click here to see answer by jim_thompson5910(13794)

Question 199021: Solve the given proof for L. Include the rule and premise(s) from which each step was derived.
1. ( R * S) v (R * ~E) Pr.
2. (Y * O) > (E * ~S) Pr.
3. (O > ~Y) > L Pr. / .: L

Click here to see answer by jim_thompson5910(13794)

Question 199064: I', new to this site please help my teacher says this is incorrect. please help thank you.

1.Write the negation for the statement below.
Someone in the family makes bread.

Click here to see answer by jim_thompson5910(13794)

Question 199525: If you could help me to solve thiss proof I would really appreciate it. I think that I need to set up either a constructive dilema or Demorgans Rule but I can't seem to figure out how.
F>(S>~J)
D>(F.J) solution: ~Dv~S
Click here to see answer by jim_thompson5910(13794)

Question 199524: If you could help me to figure out this problem I would really appreciate it. I've tried implication, transitivity and i still can't seem to get it.
1.C>A
2.B>C solution:(CvB)>A
Click here to see answer by jim_thompson5910(13794)

Question 199553: If you could help me with the problem I would really appreciate it. I finished it in 19 lines but i think I did a few steps wrong.
1. B=W
2. L>B
3. ~Bv~W /~(WvL)
Click here to see answer by jim_thompson5910(13794)

Question 199701: Solve the given proof for D. Include the rule from which each step was derived.
Given: A → ~B
~(C^~A)
B
~C→D
Prove: D

Click here to see answer by jim_thompson5910(13794)

Question 201125: Can someone please help me with these two statements are they true of false
1. Some rational numbers are irrational.
2. The absolute value of any nonzero number is an irrational number.
Click here to see answer by jim_thompson5910(13794)

Question 201425: Hello, I need help with these proofs. I believe they are propositional logic and require rules 1-13 involving everything from Modus Ponens to Double Negation.
1. Gv(R&E)
2. (GvE)>~R
conclusion: GvM
using rules of replacement and inference.
Click here to see answer by jim_thompson5910(13794)

Question 205446: I need help finishing this proof.
1. ~ (A v B)
2. E > B
3. E v (G > U)
4. H v (W & X)
5. (H v X) > (U > O) / G > O
Click here to see answer by jim_thompson5910(13794)

Question 205447: I need help finishing this proof.
1. (A v B) v C
2. ~B & ~ E
3. (A v C) > (E & W) / ~ (~E v ~ W)
Click here to see answer by jim_thompson5910(13794)

Question 209979: is there a formula to figure out the sides of a triangle, when the perimeter equals 76 cm. the 2nd side is 2x the 1st side and the 3rd side is 4 cm shorter than the the 2nd side. please help.
Click here to see answer by Earlsdon(4900)

Question 210029: I need a proof of the Material Equivalence equivalence rule. (solved both ways)
Click here to see answer by nyc_function(260)

Question 217826: If a, b are elements of the REAL numbers and a+b=0, then a= -b.
I am having trouble with the steps, I kinda of know what types of axioms I need to use. Inverse and DEF. of Subtraction are some of those.
Click here to see answer by drj(1380)

Question 225178: Premise: (A & B) v C
Conclusion: C v B
Click here to see answer by jim_thompson5910(13794)

Question 225400: why is it when a odd number is added to an odd number its always even, and when a odd number is multilied by a odd number its always odd.
Click here to see answer by RAY100(1637)

Question 227930: I need help finishing this proof.
(P<->Q)->R,P->Q,Q->P |-R
1 (1) (P<->Q)->R A
2 (2) P->Q A
3 (3) Q->P A
Click here to see answer by jim_thompson5910(13794)

Question 227929: I need help solving this proof.
P,QvR,~RvS,~Q |- P&S
1 (1) P A
2 (2) QvR A
3 (3) ~RvS A
4 (4) ~Q A
Click here to see answer by jim_thompson5910(13794)

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