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#1 2012-03-22 12:25:59
- TARAJS
- Member
- Registered: 2011-12-01
- Posts: 19
Not a problem but need help with definitions
I'm writing a paper on the difference between Reductio ad absurdom vs Indirect proof... everything i find is telling me that an indirect proof is a type of Reductio ad absurdom or they are the something.. any help would be wonderful.
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#2 2012-03-22 12:44:58
- bobbym
- bumpkin
- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 109,606
Re: Not a problem but need help with definitions
Reductio ad absurdum ( proof by contradictiction ) means you fight your way to a contradiction. A famous one is the proof that the √ 2 is irrational. You can use infinite descent which is Reductio ad absurdum or you can use the rational root theorem which is a direct proof.
In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.
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#3 2012-03-23 12:42:38
- TARAJS
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- Registered: 2011-12-01
- Posts: 19
Re: Not a problem but need help with definitions
I'm still a little confused...
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#4 2012-03-23 13:12:56
- bobbym
- bumpkin
- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 109,606
Re: Not a problem but need help with definitions
Hi;
One is a direct proof of an assertion. The other assumes the assertion is true and then works towards a contradiction.
In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.
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#5 2012-03-23 15:11:32
- Bob
- Administrator
- Registered: 2010-06-20
- Posts: 10,136
Re: Not a problem but need help with definitions
hi TARAJS,
As this is just a question of definition, I googled 'indirect proof'. The top 6 hits all said they are the same thing.
Wiki, for example says
Proof by contradiction is also known as indirect proof, apagogical argument, reductio ad impossibilem
Bob
Children are not defined by school ...........The Fonz
You cannot teach a man anything; you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you! …………….Bob 
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