Proof: -(-n) = n

[danbaron]

I'm translating what I have for the Toom-Cook multiplication algorithm from PowerBasic to Fortran.

I previously translated it from C to PowerBasic.

It is boring and tedious.

So, I downloaded, and have been fooling with MathMagic.

http://www.mathmagic.com/

Below, is a tiny bit of abstract algebra.

I don't know much of it.

I do know that when students first see it, usually they don't like it.

I think partly it is because, in it you prove things that you previously thought of as obvious.

But, you soon find out that knowing something is true, and proving it is true, are two different things.

Here is (most of) a proof that, for any integer, n, -(-n) = n.

(I just saved the MathMagic file as a PNG file.)

inverse.jpg

[REDEBOLT]

Very Interesting. I like math too.



Regards,
Bob