Assignment 13 Query

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course Mth 151

12/11 11

013. `query 13

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Question: `q3.2.6 ~(p^q) false; truth values of components

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Your solution:

The truth values are both p & q

confidence rating #$&*:3

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Given Solution:

`a**The question asks for the truth values of p and q that would make the statement ~(p^q) false. If ~(p^q) is false then p^q is true, which means that both p and q must be true.**

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Self-critique (if necessary):

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Self-critique Rating:3

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Question: `q3.2.18 p false q true ~[(~p^~q) U ~q]

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Your solution:

The first part is false and second part is false, ~[FalseUFalse] taking the negation of a false statement is true

confidence rating #$&*:2

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Given Solution:

`a**~p ^ ~q is false because ~q is false. One false is fatal to a conjunction.

~q is false so both parts of the disjunction [(~p^~q) U ~q] are false. Thus [(~p^~q) U ~q] is false.

The negation ~[(~p^~q) U ~q] of this statement is therefore true.**

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Self-critique (if necessary):

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Self-critique Rating:3

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Question: `q3.2.36 p: 15<8 q: 9 not > 5 r: 18 <= 18 evaluate -(p U -q) U -r

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Your solution:

I am not sure how to go about this problem

confidence rating #$&*:

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Given Solution:

`a** p and q are both false statements, while r is a true statement.

It follows that p U ~q is true: since ~q is true the disjunction is true.

It therefore follows that ~(p U ~q) is false.

Since r is true, ~r is false.

Thus ~(p U ~q) U ~r is a disjunction of two false statements, ~(p U ~q) and ~r.

A disjunction of two false statements is false.

So the statement is false. **

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Self-critique (if necessary):

@&

&#Your response did not agree with the given solution in all details, and you should therefore have addressed the discrepancy with a full self-critique, detailing the discrepancy and demonstrating exactly what you do and do not understand about the parts of the given solution on which your solution didn't agree, and if necessary asking specific questions (to which I will respond).

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Self-critique Rating:

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Question: `q (formerly 3.2.42) This wasn't assigned, but you should be able to answer based on your responses to similar assigned questions. {}{}How many rows are there in a statement involving p,q,r,s,u,v,m,n? Note that rows go across the page. For example a statement involving just p and q will have four rows, one each for TT, TF, FT and FF. The headings (i.e., p, q and whatever other statements are necessary to evaluate the truth table) might also be considered a row, but for this problem do not consider the headings to be a row.

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Your solution:

confidence rating #$&*:

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Given Solution:

`a** If you just have two statements p and q, then there are four possible truth values: TT, TF, FT and FF.

If you have three statements p, q and r then there are eight possible truth values: TTT, TTF, TFT, TFF, and FTT, FTF, FFT, FFF.

Note that the number of possible truth values doubles every time you add a statement.

The number of truth values for 2 statements is 4, which is 2^2.

For 3 statements this doubles to 8, which is 2^3.

Every added statement doubles the number, which adds a power to 2.

From this we see that the number of possible truth values for n statements is 2^n.

For the 8 statements listed for this problem, there are therefore 2^8 =256 possible truth values. **

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Self-critique (if necessary):

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Self-critique Rating:

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Question: `q3.2.56 (fomerly 3.2.54) This was not assigned but based on your work on similar problems you should be able to construct the truth table for (-p ^ -q) U (~p U q). Give your truth table:

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Your solution:

I haven’t quite figured this out yet

confidence rating #$&*:

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Given Solution:

`a** For column headings

p q ~p ~q ~p^~q ~p U q (~p^~q) U (~p Uq)

the first row would start off T T, for p and for q. Then F F for ~p and ~q. Then F for ~p ^ ~q, then T for ~p V q, then T for the final column.

So the first row would be

T T F F F T T.

The second row would be

T F F T F F F

The third row would be

F T T F F T T

and the fourth row would be

F F T T T T T **

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Self-critique (if necessary):

@&

&#You did not answer the given question. You need to always at least explain what you do and do not understand about the question. A phrase-by-phrase analysis is generally required when you cannot otherwise answer a question.

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Self-critique Rating:

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Question: `q3.2.68 (formerly 3.2.66) This wasn't assigned but is similar to other assigned problems so you should be able to solve it: Negate the following statement using De Morgan's Law: ' F.C. tried to sell the wine but was unable to do so'.

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Your solution:

FC did not try to sell the wine and was unable to do so

confidence rating #$&*:2

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Given Solution:

`a** We use two ideas here. The first is that 'but' is interpreted as 'and'; and the second is that the negation of an 'and' statement is an 'or' statement. deMorgan's Laws say that the negation of p OR q is ~p AND ~q, while the negation of p AND q is ~p OR ~q.

The given statement ' F.C. tried to sell the book but was unable to do so' can be symbolized as 'p ^ q'. Its negation would be ~(p ^ q) = ~p U ~q. We translate this as 'F.C. didn't try to sell the book or he sold it', or something equivalent. **

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Self-critique (if necessary):

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Self-critique Rating:1

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Question: `q3.2.81 is the statement 3 + 1 = 6 xor 2 + 5 = 7 true or false?

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Your solution:

This is true because it only needs one part to be true for it to be true

confidence rating #$&*:3

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Given Solution:

`a** For an XOR statement exactly one part has to be true. The statement is true because the second part is true and the first is false.

We need exactly one true statement; if both parts were true the XOR wouldn't be. **

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Self-critique (if necessary):

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Self-critique rating:

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Question: `q3.2.81 is the statement 3 + 1 = 6 xor 2 + 5 = 7 true or false?

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Your solution:

This is true because it only needs one part to be true for it to be true

confidence rating #$&*:3

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Given Solution:

`a** For an XOR statement exactly one part has to be true. The statement is true because the second part is true and the first is false.

We need exactly one true statement; if both parts were true the XOR wouldn't be. **

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Self-critique (if necessary):

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Self-critique rating:

#*&!

&#Good responses. See my notes and let me know if you have questions. &#