Does 2 equal 1?
Uncategorized, Geeky, Math March 16th, 2007
Does 1 equal 2, you tell me? 
Here is the proof (unfiltered by rational arguments):
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- Let a and b be equal non-zero quantities
- a = b
- Multiply through by a
- a2 = ab
- Subtract b2
- a2 − b2 = ab − b2
- Factor both sides
- (a − b)(a + b) = b(a − b)
- Divide out (a − b)
- a + b = b
- Observing that a = b
- b + b = b
- Combine like terms on the left
- 2b = b
- Divide by the non-zero b
- 2 = 1
Well, can you spot the mistake? 
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March 17th, 2007 at 6:55 am
You cannot “Divide out (a − b)” because a=b and a-b=0. You cannot divide by 0
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March 17th, 2007 at 8:08 am
Nice, that’s correct! Or should I say; that’s what makes my proof incorrect ; )
March 20th, 2007 at 12:49 pm
[…] Weeks Wiki General tips, Geeky, Math, This Weeks Wiki March 20th, 2007 Some of you might have read the post I made recently about 2 equaling 1 (congratsto Vasko for solving it). The interesting part is that I found it in Wikipedia, here is the full article on invalid (mathematical ) proofs. Really interesting! Well thats all for this Weeks Wiki, do not forget to subscribe to this blog for further updates! ^^ Share and Enjoy: These icons link to social bookmarking sites where readers can share and discover new web pages. […]
March 20th, 2007 at 12:55 pm
[…] Some of you might have read the post I made recently about 2 equaling 1 (congrats to Vasko for solving it). The interesting part is that I found this ilogical proof in Wikipedia, here is the full article on invalid (mathematical ) proofs. Really interesting! Well that’s all for this Weeks Wiki, do not forget to subscribe to this blog for further updates! ^^ Share and Enjoy: These icons link to social bookmarking sites where readers can share and discover new web pages. […]
April 2nd, 2007 at 7:12 am
[…] Remember my previous entry on 2 equaling 1? Well some people felt there was to much math so I decided to give you an easier one to understand (and cooler also) although it might not be easier to solve. Your job is to find out what happened to the missing dollar, the story goes something like this: Three old ladies went to a restaurant and ordered some food for 30$. They decided to split the money by paying 10$ each. The waiter took the money and was later told by the cashier that the food costs 25 bucks and not 30$ so he gave him 5$ dollars to give to the ladies. Now the waiter realized he could not divide the 5 bucks equal between the ladies so he decided to take 2$ him self and give them 1 dollar each (that equals 5 bucks). […]
April 29th, 2007 at 4:06 am
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