A flawed proof? (Posted on 2002-12-20)

       a=b
       a^2-ab=a^2-b^2
       a(a-b)=(a+b)(a-b)
       a=a+b
       a=a+a
       a=2a
       1=2

	Submitted by phil
Rating: 2.9167 (12 votes)
Solution:	(Hide)
The flaw, as many have pointed out, is in step 4, where both sides are "simplified", or divided by (a-b). Since we assumed that a = b, this expression is equal to zero. The proof hinges on the ability to divide both sides of the equation by zero. Since such division is illegal, the proof itself is invalid.

	Subject	Author	Date
	Solution To The Problem	K Sengupta	2007-03-20 12:24:44
	iseeit.	dorkdork	2003-08-02 22:09:49
	Solution	rajesh	2003-06-30 21:11:55
	No no	michael	2003-04-12 04:31:45
	Not really	Gamer	2003-04-11 09:52:01
	No Subject	N__A__T__A	2003-01-03 07:42:18
	1st post, correct solution (i think)	Aim Jayy	2002-12-25 22:11:06
	Solution	Jen	2002-12-25 10:51:33
	Solution	Gautam Joshi	2002-12-23 14:18:27
	solution	ananth	2002-12-21 17:10:22
	re(2): A flawed proof? ( Solution )	Ravi Raja	2002-12-21 07:21:16
	re: A flawed proof? ( Solution )	Dulanjana	2002-12-21 05:56:58
	A flawed proof? ( Solution )	Ravi Raja	2002-12-20 19:14:19