You know I was always bloody awful at Algebra when I was at school.

One day I had to do this Algebra sum when I got into a dreadful muddle

Here goes let a=b
Then          a**2=b**2
and           a**2-b**2=0
and           a**2-b**2=a**2-b**2
so            (a+b)(a-b)=a**2-b**2
and further   (a+b)(a-b)=a(a-b)
and so of course (a+b) = a
and (as a=b)      2a=a
AND                1=2  
oops
Where did i go wrong????
DPRK007

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Request for Question Clarification by pinkfreud-ga on 16 Oct 2006 16:20 PDT

Here's a similar problem with an explanation. Does this help?

http://mathforum.org/library/drmath/view/55792.html

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Clarification of Question by dprk007-ga on 16 Oct 2006 16:35 PDT

Very good and very Quick, Pink

The internet though sometimes spoils all the fun

(even thogh my notation was a bit different)

DPRK007

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Request for Question Clarification by pinkfreud-ga on 16 Oct 2006 16:42 PDT

Would the link that I posted be fully satisfactory as an answer? The
concept is, I think, the same as your problem. The hidden error is a
division by zero.

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Clarification of Question by dprk007-ga on 16 Oct 2006 16:50 PDT

yip
go for it

Thanks for accepting the link I posted as your official answer!

I've seen this nifty 1=2 problem presented in many different ways,
with the catch being that there is a disguised instance of dividing by
zero. I used this search string to find an online reference:

Google Web Search: "1=2" "divide OR dividing by zero"
://www.google.com/search?hl=en&q=%221%3D2%22+%22divide+OR+dividing+by+zero%22

Regarding the matter of the Internet spoiling the fun, I feel a bit
guilty, so here is a mathish joke as an attempt to restore some of the
fun:

A statistician and two mathematicians go hunting. When they see a
rabbit, the first mathematician shoots, missing it on the left. The
second mathematician shoots and misses it on the right.

The statistician shouts: "We've hit it!" 

Best regards,
pinkfreud

Great Stuff, Pink

You might enjoy knowing that Einstein himself worked on this problem:
http://members.cox.net/sublime_1/einsteinshow.jpg

http://www.mortalwombat.com/Special/Thus_Do_I_Refute_Subbie.jpg

Wow, Pink, THAT (the image) was VERY clever.

I bet that Subby will neverest until he can reciprocate.

Bryo

Naw, I was expecting such a web-wise woman to set our audience
straight...especially since I left her such a searchable hint
in the image name...  ; )

dprk007,

Thanx for the five stars and the tip!

~pinkfreud

so            (a+b)(a-b)=a**2-b**2
and further   (a+b)(a-b)=a(a-b)

u start to load a=b here

and so of course (a+b) = a
and (as a=b)      2a=a

here u load a=b one more time so u got that 2