Prove All Numbers Equal: No 0 Needed!

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The discussion centers around a proof claiming that all numbers are equal, presented without involving zero. The proof manipulates algebraic expressions to ultimately derive that a equals b. However, participants point out errors in the reasoning, particularly in the handling of equalities and square roots. One participant highlights that adding terms like a^2 - a^2 and b^2 - b^2 to both sides does not alter the equality, while another emphasizes that taking square roots requires consideration of both positive and negative solutions. The conversation reveals confusion over the algebraic steps and the implications of the proof, ultimately questioning the validity of the conclusion that all numbers are equal.
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All numbers are equal :D

heres the latest proof and it doesn't involve 0 anywhere. no term like (a-b) is involved unlike other similar proofs

-ab = -ab
=> a^2 - a^2 - ab = b^2 - b^2 - ab
=> a^2 - a(a+b) = b^2 - b(a+b)
=> a^2 - a(a+b) + (a+b)^2/4 = b^2 - b(a+b) + (a+b)^2/4

as (x-y)^2 = x^2 - 2xy + y^2,

[a - (a+b)/2]^2 = [b - (a+b)/2]^2

taking square roots,

a - (a+b)/2 = b - (a+b)/2
a = b

hence proved :D

now with all numbers having been proved equal without involving "0" anywhere, what's the need to study anything :D

just noticed, this is my 1st post here after 7 years :o
 
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You can't take square roots. x^2 = y^2 does not imply x = y
If it did, this would have been your 7th post after 1 year.
 


Your second line contains an error. You added a^2 - a^2 to one side of the equation, but b^2 - b^2 to the other side. The only way for this to leave the equality unchanged is for a to equal b... so it's no surprise that you find out later that a = b.

- Warren
 


amits said:
=> a^2 - a^2 - ab = b^2 - b^2 - ab

This is the same as
a^2 + b^2 - ab = b^2 + a^2 - ab , which don't think should create any problems.
 


amits said:
[a - (a+b)/2]^2 = [b - (a+b)/2]^2

taking square roots,

a - (a+b)/2 = b - (a+b)/2
This is your error. Taking square roots leads to

a-(a+b)/2=b-(a+b)/2
or
a-(a+b)/2=-(b-(a+b)/2)

The former yields a=b. The latter yields a+b=a+b.
 


chroot said:
Your second line contains an error. You added a^2 - a^2 to one side of the equation, but b^2 - b^2 to the other side. The only way for this to leave the equality unchanged is for a to equal b... so it's no surprise that you find out later that a = b.

- Warren
That step is correct. It's just adding zero to each side.
 


chroot said:
Your second line contains an error. You added a^2 - a^2 to one side of the equation, but b^2 - b^2 to the other side. The only way for this to leave the equality unchanged is for a to equal b... so it's no surprise that you find out later that a = b.

- Warren

it isn't an error. i added a^2 + b^2 to both sides

-ab = -ab
a^2 + b^2 - ab = a^2 + b^2 - ab

a^2 - a^2 - ab = b^2 - b^2 - ab

also a^2 - a^2 = 0 & b^2 - b^2 = 0, so adding that doesn't make a difference
 


Jimmy Snyder said:
You can't take square roots. x^2 = y^2 does not imply x = y
If it did, this would have been your 7th post after 1 year.

yes, you are right. a number always has 2 square roots, 1 positive & 1 negative
 
Last edited by a moderator:


You got it wrong.
2^2 = (-2)^2
when you have sqr root you have to have either + or - sign. you only considered + sign. Consider - sign and you will get a+b = a+b
 

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