PeachParts Mercedes-Benz Forum

PeachParts Mercedes-Benz Forum (http://www.peachparts.com/shopforum/)
-   Off-Topic Discussion (http://www.peachparts.com/shopforum/off-topic-discussion/)
-   -   discrete math help (http://www.peachparts.com/shopforum/off-topic-discussion/301911-discrete-math-help.html)

jt20 07-16-2011 02:00 PM

I see it a little differently.

3X-1=mod6

there is no number you can put in X to get integer multiples of 6 on the left.

One example. 3(7/3)=1 mod6 => 7=1 mod6 ; this would be correct, but it is not a solution since 2.3333333333333333333333333333 is not an integer.

Correct me.

TheDon 07-16-2011 03:53 PM

Correct you? I don't get it.

jt20 07-16-2011 04:09 PM

I just meant that in the case that I did something wrong.

The way I see it, we need 3*(some integer) to be equal to (some integer)*6 with a remainder of 1.

Is that right?

Yak 07-16-2011 05:50 PM

Try re-writing the equation. The ~ equals the modulus in my equation

For 3x ~ 1 mod 6 to be true, 3x -1 = k6 must be true, where x and k are integers (with me so far?)

Then solve for x to see it can be an integer.

3x - 1 = k6

x - 1/3 = k2

x = k2 + 1/3

Therefore, for every case where k is an integer, x cannot be an integer so 3x ~ 1 mod 6 cannot be true.

Yak 07-16-2011 06:41 PM

Your solution in post 15 is also correct, you just didn't draw the conclusion. x and k cannot simultaneously both be integers.

"Since a  b mod m if and only if b = a+mk for some k 2 Z, adjusting an integer modulo
m is the same as adding (or subtracting) multiples of m to it." It's more legible here: http://www.math.uconn.edu/~kconrad/blurbs/ugradnumthy/modarith.pdf

The different text may also help with the other problems.

jt20 07-16-2011 06:48 PM

Quote:

Originally Posted by Yak (Post 2753016)
Your solution in post 15 is also correct, you just didn't draw the conclusion. x and k cannot simultaneously both be integers.

ditto

TheDon 07-16-2011 10:47 PM

Quote:

Originally Posted by Yak (Post 2753016)
Your solution in post 15 is also correct, you just didn't draw the conclusion. x and k cannot simultaneously both be integers.

"Since a  b mod m if and only if b = a+mk for some k 2 Z, adjusting an integer modulo
m is the same as adding (or subtracting) multiples of m to it." It's more legible here: http://www.math.uconn.edu/~kconrad/blurbs/ugradnumthy/modarith.pdf

The different text may also help with the other problems.

so I was correct but I didn't conclude.

So what would my conclusion look like.. math symbols or just saying "x cannot be an integer because for every 2k+1/3, there is no x such that x belongs to Z"

Yak 07-17-2011 09:46 AM

Quote:

Originally Posted by TheDon (Post 2753118)
so I was correct but I didn't conclude.

So what would my conclusion look like.. math symbols or just saying "x cannot be an integer because for every 2k+1/3, there is no x such that x belongs to Z"

A proof won't be considered "correct" simply because your conclusion appears the same. You need to define the criteria the equation needs, then show your work on how the equation meets that criteria, then conclude.

The level of documentation really depends on your teacher. Showing your work is important. It's been a long time since I've done proofs, but something like the following may work.

"Therefore, for 3x ~ 1 mod 6; x {insert symbol for not a member of} Z" or

"Therefore, 3x {insert symbol for not congruent to} 1 mod 6"

Either of these conclusions are true and prove the original is not correct, but it depends on which is most satisfactory to your teacher

leathermang 07-17-2011 10:53 AM

Quote:

Originally Posted by rs899 (Post 2752382)
I disagree. WGAS at our advanced ages. Art history, music, language, I can see, but math? I am checking out of this one....

I was not trying to check in to this one... because I can not...
but just wanted them to ' label ' the subject...
I took ' discrete ' to mean ' confidential ' since it was not capitalized ... and could not figure out why math needed to be confidential...
LOL

TheDon 07-17-2011 10:28 PM

http://i3.photobucket.com/albums/y74...rx24/page2.jpg

how about #5?

the triple bar has me confused.

% is mod

so

a % n = r

5 % 11 = 5

but


11 % 5 = 1

so it does not work out, correct?


As well as #1 parts A-D

A) F(10) = 0
F(2) = 2
F(55) = 0

B) F(10) = F(0)

C and D I am lost on

TheDon 07-18-2011 05:29 PM

0 bar = n bar (a bar over the 0 and n)... I need to prove it but I cannot prove it

n > 1 is a fixed natural number.


All times are GMT -4. The time now is 09:05 PM.

Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2025, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2024 Pelican Parts, LLC - Posts may be archived for display on the Peach Parts or Pelican Parts Website