# discrete math

posted by
**audryana**
.

use a direct proof to show that the product of two odd numbers is odd.

Proofs: (all the nos. i used are odd)

3 x 3 = 9

5 x 9 = 45

7 x 3 = 21

Yes, but you didn't prove the statement for "all" odd integers, only the odd integers you selected.

uhm..he didn't ask for *all* odd integers..

This is Audryana's first post

"use a direct proof to show that the product of two odd numbers is odd."

That is a general statement that means 'any' two odd numbers.

ya..so...that's wat i was saying 'any' not all..

Ok, I see you have a little to learn about logic. The terms 'any', 'for each' and 'all' are used interchangably in logic and mathematics to form universals. You provided examples, or particulars as they're called, but that didn't suggest any kind of proof. It only verified the statement for a couple cases, that's all I was trying to point out.

ok....thx for telling me that...

prove the square root of 2 is irrational

Can you show me how f of X function 6X-9 Is unto or one to one.