[Vorbis-dev] Window function (again)

[bender at doanstar.de]

Hello,

I'm searching some information about the Vorbis window function. I have 
read the following post from the mailing list archive (July 2003) where the 
function and its proof was explained:

http://lists.xiph.org/pipermail/vorbis-dev/2003-July/007588.html

Everything apart from one small passage was clear to me.

f^2(x) + f^2(n/2+x) = 1
<=> f^2(x) + f^2(n/2-x) = 1 <-- here in this line
<=> sin^2(pi/2*pi*g(z)) + sin^2(pi/2*pi*g(1-z)) = 1

Well, I do not know how to eliminate the Variable n in the second line.

Could anyone help me? That would be nice...

Regards,
Duc