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Chapter 13 - Exercises

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jeanbodemer

Chapter 13 - Exercises
October 24, 2007 08:50PM

Registered: 18 years ago
Posts: 470
Rating: 0

Does anyone know how to solve 13.4

~Vx Cube(x)
-----------------
...
...
Vx ~(Cube(x) & Small(x))

I don't even know where to start.

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jeanbodemer

Re: Chapter 13 - Exercises
October 24, 2007 09:21PM

Registered: 18 years ago
Posts: 470
Rating: 0

Never mind, I managed to figure it out.

I just find it hard to believe that no-one had problems with the exercises in chapter 13.

Am I the only one or am I just stupid? confused smiley

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Tracey

Re: Chapter 13 - Exercises
October 24, 2007 10:04PM

Registered: 18 years ago
Posts: 3,249
Rating: 0

I haven't done any yet.
I'm got an exam tomorrow so I won't have much time for COS261.

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jeanbodemer

Re: Chapter 13 - Exercises
October 24, 2007 10:11PM

Registered: 18 years ago
Posts: 470
Rating: 0

That really sucks Tracey! eye popping smiley

Luckily that hasn't happened to me yet.

What are you writing?

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Tracey

Re: Chapter 13 - Exercises
October 24, 2007 11:01PM

Registered: 18 years ago
Posts: 3,249
Rating: 0

I wrote MAT103- PreCalculus on Tuesday and MAT112 - Calculus tomorrow.

I've been through the textbook but I really need to do alot of exercises and learn the rules for formal proofs.

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jeanbodemer

Re: Chapter 13 - Exercises
October 25, 2007 12:04AM

Registered: 18 years ago
Posts: 470
Rating: 0

Exercise 13.8

Universal Elim only allows you to remove two universals from a sentence when they are at the front of a sentance. I've been unable to move the middle universal to the front in Fitch as we are only allowed to use Taut Con.

Ax (Cube(x) -> Ay (~Dodec(y) | FrontOf(x, y)))

Some pointers please!

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Reanie

Re: Chapter 13 - Exercises
October 25, 2007 07:53AM

Registered: 18 years ago
Posts: 3,015
Rating: 5

Haven't gone through all the exercises as well, definately not at chapter 13. From Chapter 10, stuff is still very hazy!

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visnaicker

Re: Chapter 13 - Exercises
October 25, 2007 08:03AM

Registered: 18 years ago
Posts: 518
Rating: 0

Nothing after chapter 6 went in properly. I am gonna work thru the assignments only, and hope to use the pattern to answer the exam. I am hopeless in this subject.

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Reanie

Re: Chapter 13 - Exercises
October 25, 2007 08:10AM

Registered: 18 years ago
Posts: 3,015
Rating: 5

I've managed to do the full first assignment of 2005 (available from Osprey) without any difficulties. But, as we all know, it gets more difficult later on... Luckily I had to go through a similar excercise for COS351 which also have a bit of FOL.

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jeanbodemer

Re: Chapter 13 - Exercises
October 25, 2007 09:35AM

Registered: 18 years ago
Posts: 470
Rating: 0

I managed to figure it out. Always seems so simple once you've done it.

This is how, if anyone is interested.

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visnaicker

Re: Chapter 13 - Exercises
October 25, 2007 01:28PM

Registered: 18 years ago
Posts: 518
Rating: 0

Thanks for the offers of help but I am only looking for 35-45%, so I can do the supp. I am going to study certain parts really well. Unfortunately, I am being guilted into doing my day job, so I cannot get any leave, I will have to turn up to the office tommorrow morning, and I've been guilted into working from 7am-6pm for so long, Saturdays and sundays as well, that I just could not do enoguh the work during the year. It sucks.

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AndreB

Re: Chapter 13 - Exercises
October 25, 2007 05:58PM

Registered: 18 years ago
Posts: 1,501
Rating: 0

I've only started on Quantifiers now. Spent the last day or 2 on all the material upto and including Assign02. It's made more sense this time around. Just wish I had 2 more days.
But, alas - it is what it is. The night before with 5 chapters to go.
It's going to be a long one.
All the best for tomorrow.

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FerdieL

Re: Chapter 13 - Exercises
October 25, 2007 08:06PM

Registered: 17 years ago
Posts: 136
Rating: 0

I just hope to get my 46% so I can pass with the yearmark.....

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Reanie

Re: Chapter 13 - Exercises
October 25, 2007 08:51PM

Registered: 18 years ago
Posts: 3,015
Rating: 5

I'm so glad I was forced to do a quick "update" on the quantifiers for the Cos351 exam. But, it was a very quick update, so I need to redo the "update" again. Luckily we are writing in the afternoon. It is just poor Vis that has to work the morning before!! Very bad deal that he got.

Good luck to everyone - I hope they ask the nice easy questions!

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Tracey

Re: Chapter 13 - Exercises
October 25, 2007 08:55PM

Registered: 18 years ago
Posts: 3,249
Rating: 0

Doesn't sound like too many people are looking forward to this exam or expect tp do well.
I'm really enjoying the subject so I want to see how well I can do, that said I still need to put in a lot of work on formal proofs wrt quantifiers though.

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jeanbodemer

Re: Chapter 13 - Exercises
October 25, 2007 08:59PM

Registered: 18 years ago
Posts: 470
Rating: 0

I'm looking forward to this and think that I should do pretty well.

Just scared that I might panic when given some weird proof. eye popping smiley

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jeanbodemer

Re: Chapter 13 - Exercises
October 25, 2007 10:47PM

Registered: 18 years ago
Posts: 470
Rating: 0

Last years exam tutorial is much more difficult than this years tutorial. It has dampened my spirits a bit. sad smiley

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Tracey

Re: Chapter 13 - Exercises
October 26, 2007 08:53AM

Registered: 18 years ago
Posts: 3,249
Rating: 0

The sample paper that they sent us didn't look too bad.

Look at the bottom of page 4 and page 5 in tut letter 106 for hints on how to
do quanitifer formal proofs.

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jeanbodemer

Re: Chapter 13 - Exercises
October 26, 2007 09:18AM

Registered: 18 years ago
Posts: 470
Rating: 0

I'm talking about the exam tutorial letter from 2006. It looks like a more complete exam paper and is more difficult than the one we were given this year.

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jeanbodemer

Re: Chapter 13 - Exercises
October 26, 2007 09:36AM

Registered: 18 years ago
Posts: 470
Rating: 0

You can download it from here Download - 2006 Exam Tutorial

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Tracey

Re: Chapter 13 - Exercises
October 26, 2007 09:47AM

Registered: 18 years ago
Posts: 3,249
Rating: 0

I've got that, I'm going to work through it as soon as I've completed this year's assignments and exam paper.

I hopw the studying's going well, I have a mug of chai tea and am going for it. smileys with beer

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Reanie

Re: Chapter 13 - Exercises
October 26, 2007 10:04AM

Registered: 18 years ago
Posts: 3,015
Rating: 5

I'm actually, at this stage, considering that I might actually pass this subject....

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Tracey

Re: Chapter 13 - Exercises
October 26, 2007 10:19AM

Registered: 18 years ago
Posts: 3,249
Rating: 0

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jeanbodemer

Re: Chapter 13 - Exercises
October 26, 2007 11:24AM

Registered: 18 years ago
Posts: 470
Rating: 0

Are we allowed to refer to previous theorems when doing our proofs? Where do we draw the line?

For example, here is my proof for Assignment 2 - Q 1.4. It is significantly longer than the answer provided and I don't want to waste my time when I can just say "prev theorem DeMorgan".