• Oct 14th 2008, 03:39 PM
olenka
1. Prove: for all a ϵ Z, for all b ϵ Z if a│b then a²│b²

2. Prove: for all n ϵ Z, n is add if and only if n² is odd.

3. using the definition of equal sets and the definition of subset, prove this

form of DeMorgan's Law:____ _ _
If A and B are sets then AUB=A∩B

• Oct 15th 2008, 12:29 PM
Moo
Hello,
Quote:

Originally Posted by olenka
1. Prove: for all a ϵ Z, for all b ϵ Z if a│b then a²│b²

If a|b, then b=ka
square both sides =)

Quote:

2. Prove: for all n ϵ Z, n is odd if and only if n² is odd.
If n is even, then n=2n' ---> n²=...
If n is odd, then n=2n'+1 ---> n²=...

Quote:

3. using the definition of equal sets and the definition of subset, prove this

form of DeMorgan's Law:____ _ _
If A and B are sets then AUB=A∩B
$A \cap B \subseteq A \cup B$

This may be all you need eh ? (Surprised)
• Oct 15th 2008, 03:48 PM
olenka
ehhhh ....help
Quote:

Originally Posted by Moo
Hello,

If a|b, then b=ka
square both sides =)

If n is even, then n=2n' ---> n²=...
If n is odd, then n=2n'+1 ---> n²=...

$A \cap B \subseteq A \cup B$

This may be all you need eh ? (Surprised)

Hi, thanks for that , but could U be more specific...and show me exactly step by step process of solving that problems??? (Itwasntme) Thanks!!
• Oct 19th 2008, 12:43 AM
Moo
Quote:

Originally Posted by olenka
Hi, thanks for that , but could U be more specific...and show me exactly step by step process of solving that problems??? (Itwasntme) Thanks!!

Yo,

What don't you understand exactly ? Have you at least tried to do them ? (Doh)
• Oct 20th 2008, 08:40 PM
olenka