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-   -   Set theory MOD Help. (http://mymathforum.com/algebra/25522-set-theory-mod-help.html)

 MathsLOL March 5th, 2012 04:09 AM

Set theory MOD Help.

If E = { n e Z:1 =< n =< 12}

A={n e Z:12 mod n=0}
B={n e E: n is a prime number}
C={n e Z: n mod 1=2}

Enumerate the elements of

A U B

______
(A U C)

C - A

Could someone explain in steps how to solve this question?

 ZardoZ March 5th, 2012 04:56 AM

Re: Set theory MOD Help.

[color=#000000]The first thing you have to do is to specify the elements of each set. I made some changes because I think that there are problems in the wording of the exercise.

$E=\{1,2,3,4,5,6,7,8,9,10,11,12\}$

$A=\{{n\in E:\;12\equiv 0 \,\pmod{n}\,\}=\{ 1,2,3,4,6,12\}$

$B=\{n\in E:\;n\in\mathbb{P}\}=\{1,2,3,5,7,11\}$

$C=\{n\in E:\; n\equiv 1\, \pmod{2}\,\}=\{ 1,3,5,7,9,11\}$

[/color]

 skipjack March 5th, 2012 06:29 AM

To typeset an arithmetic congruence using the latex tag, please use \pmod as illustrated below:

$x\equiv y\,\pmod n$   (based on x\equiv y\,\pmod n).

 MathsLOL March 5th, 2012 07:31 AM

Re: Set theory MOD Help.

Thanks for all the help.

 ZardoZ March 6th, 2012 11:52 AM

Re:

Quote:
 Originally Posted by skipjack To typeset an arithmetic congruence using the latex tag, please use \pmod as illustrated below: $x\equiv y\,\pmod n$   (based on x\equiv y\,\pmod n).

[color=#000000]Ok I corrected it, I tried to use \mod but it didn't work here![/color]

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