# Math Help - Math Proof: 2=1

1. Originally Posted by ThePerfectHacker
People must die for their false beliefs.
my point is that no one believes the "proofs" here. they're like mathematical jokes... on another level

2. Originally Posted by janvdl
Isn't that a bit harsh?
Probably. I tend to be a bit carried away when I post.

Well, my point is that the way we represent certain mathematical concepts in symbols can be misleading. For example, representing the imaginary number i as $\sqrt{-1}$ can mislead us into manipulating equations using rules for $\sqrt{x}$ that only apply only when $x\geq0$.

3. Originally Posted by ThePerfectHacker
People must die for their false beliefs.
Oh no! What have I done?

4. Originally Posted by TriKri
Oh no! What have I done?
Don't worry, be happy!

5. Ok, group hug everyone!

our group is Abelian, so it doesn't matter who hugs who in which order, just grab a partner

6. Originally Posted by Jhevon
Ok, group hug everyone!

our group is Abelian, so it doesn't matter who hugs who in which order, just grab a partner
I've got a fiancee already, but I can grab a pretty girl?

-Dan

7. Originally Posted by Jhevon
Ok, group hug everyone!

our group is Abelian, so it doesn't matter who hugs who in which order, just grab a partner
I hug Jhevon first!
Originally Posted by topsquark
I've got a fiancee already, but I can grab a pretty girl?

-Dan
If by "grab" you mean "acquire" for a platonic group hug, then yes. If by "grab" you mean "grope" / "pinch" / "fondle" / "caress" / "stroke" / "pet" or any other activity which could potentially "raise" your "morning sun" then...

only if it's consentual.

8. Originally Posted by angel.white
If by "grab" you mean "acquire" for a platonic group hug, then yes. If by "grab" you mean "grope" / "pinch" / "fondle" / "caress" / "stroke" / "pet" or any other activity which could potentially "raise" your "morning sun" then...

only if it's consentual.
(sighs) Only that kind of detail can come from a Math forum!

-Dan

9. Originally Posted by Jhevon
Ok, group hug everyone!

our group is Abelian, so it doesn't matter who hugs who in which order, just grab a partner
I'm with Topsquark(his idea not him )... But we only have 1 girl here...

10. Originally Posted by topsquark
I've got a fiancee already, but I can grab a pretty girl?

-Dan
Same here, when is your big date Dan?

11. Originally Posted by Quick
It hasn't been proven that $\sqrt{-1\cdot-1}=\sqrt{-1}\cdot\sqrt{-1}$
given
Sqrt-1*Sqrt-1

Prove
Sqrt-1*Sqrt-1

Justifications
Sqrt-1=i
therefore: Sqrt-1*Sqrt-1= i^2
Sqrt(-1*-1) = Sqrt-1*Sqrt-1 = i^2
i^2=i^2

if i am correct. i hope

12. Originally Posted by Alfarom
given
Sqrt-1*Sqrt-1

Prove
Sqrt-1*Sqrt-1

Justifications
Sqrt-1=i
therefore: Sqrt-1*Sqrt-1= i^2
Sqrt(-1*-1) = Sqrt-1*Sqrt-1 = i^2
i^2=i^2

if i am correct. i hope
The problem is that
$\sqrt{-1 \cdot -1} = \sqrt{1} = 1 \neq i^2$

You have assumed that $\sqrt{-1 \cdot -1} = (\sqrt{-1})^2$ in the third line of your justification. This is what you were trying to prove.

-Dan

Page 4 of 4 First 1234