Chapter 6.3 Indirect Proofs(You might want to read this before reading David's scribe because he spoils the..... next...... Scribe!!!!!!!!!!!!! So read this first!!!!This is possibly the longest title ever, of all time)

Indirect Proofs!!!!!!!!

A long time ago, (since September, 2011) in this class, we have been using proofs. Now they turn out to be direct proofs. At times, they are difficult to find a direct proof so it's possible to reason indirectly. To use a indirect proof, you assume temporarily that the desired conclusion is not true. Since I don't want to explain how to write a indirect prof, I'll write it in steps so... everyone... is... happy!!!

How to write Indirect Proofs!!!!!!!!!!!
Steps
1. Assume temporarily that the conlusion is not true!
2.Reason logically until you reach a contradition of a known fact!
3.Point out that the temporary assumption must be false, and that the conclusion must then be true!

Here is a example of using indirect proofs from the book.


Given: n is an interger and n squared (I don't have microsoft word on my computer so i wrote squared) is even.
Proof: n is even
Assume temporarily that n isnot even. Then n is odd, and
n squared = n x n
               = odd x odd x = odd
But this contradits the given information that n squared is even. Therefore the temporarily assumption that n is not false. It follows that n is even.

Now is time for the epic question of the day!!!








Are you ready?





















Did you know that provig the contrapositive of a statement is related to indirect proofs?


Confused? Here's an example from the book!

If you want to prove the statement " If p, then q," you can prove the contrapositive " if not q, then p." Or you could write an indirect proof- assume that q is false and show that this assumption implies that p is false.


Now comes the epic videos of the day!!




http://www.5min.com/Video/How-to-Write-an-Indirect-Proof-516909808


This is the only video that I could find that was not on youtube. Somehow, searching for a video on indirect proofs can lead you to Call of Duty Black Ops?


So that is chapter 6.3!!!!!! Prepare for more epic questions and videos of the day!!! Also, expect a epic picture of the day if there is any picture to show.

Now the next scribe is...
Not Jimmy Bob
















Not John Bob













Not me




But it's



























Whoever David picked!!!!!!!!!!