Hey guys,

So in a universal set that $\displaystyle x$ are all natural numbers and $\displaystyle x \le 12$

does $\displaystyle C = \{ x | 3|x \}$ mean all positive integers divisible by 3?

So in this case it would be 3, 6, 9, 12 ?

thanks!

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- Mar 19th 2010, 06:19 PMjvignacioUniversal set question.
Hey guys,

So in a universal set that $\displaystyle x$ are all natural numbers and $\displaystyle x \le 12$

does $\displaystyle C = \{ x | 3|x \}$ mean all positive integers divisible by 3?

So in this case it would be 3, 6, 9, 12 ?

thanks! - Mar 20th 2010, 01:47 AMemakarov
I would say so.

To avoid confusing notation, it is possible to replace the first vertical bar with a colon: $\displaystyle \{x:3\mathrel{\vert} x\}$. - Mar 20th 2010, 06:08 AMjvignacio
thanks for that idea and reply.

Also if:

in a universal set that http://www.mathhelpforum.com/math-he...155c67a6-1.gif are all natural numbers and http://www.mathhelpforum.com/math-he...d6fd9e79-1.gif,

$\displaystyle A= \{ 3,4,5,6,7,8,9,10 \}$

$\displaystyle B = \{ 9, 10, 11 \}$

$\displaystyle C = \{ 3,6,9,12 \}$

whats $\displaystyle (A\cup \overline{B}) \cap C =$ ?

Would I start with the brackets $\displaystyle (A\cup \overline{B})$ then get that result and work out $\displaystyle [RESULT] \cap C$ ? Also i cant figure out $\displaystyle \overline{B} $ from the B set... any help? thank you! - Mar 20th 2010, 06:18 AMemakarovQuote:

Would I start with the brackets http://www.mathhelpforum.com/math-he...20e7ed0b-1.gif then get that result and work out http://www.mathhelpforum.com/math-he...f0faa959-1.gif ?

Quote: - Mar 20th 2010, 06:25 AMjvignacio
- Mar 20th 2010, 07:03 AMPlato
That is correct if your text material does not include 0 as a natural number.

- Mar 20th 2010, 08:18 AMjvignacio
- Mar 21st 2010, 02:34 AMjvignacio
- Mar 21st 2010, 06:43 AMemakarovQuote:

what would go first if its something like this? the http://www.mathhelpforum.com/math-he...4fc5de9c-1.gif?