Not that I don't appreciate the snide commentary, but this is why I'm asking. You can't forget the sin*sin part. i stands for "imaginary". (slowly: i is "imaginary"). Turning the product of sines into the negative product of sines is imaginary. There is no number that, squared, equals -1. There is no number that, squared, equals -1. It's not really there.
Date: Mon, 07 Nov 2005 20:58:36 +0100
From: Piotr Majdak <piotr@majdak.com
>
Subject: Re: [PD] basic DSP stuff
Cc: Pure Data List <pd-list@iem.at>
Message-ID: <436FB1EC.80908@majdak.com>
Content-Type: text/plain; charset=us-ascii; format=flowed
Chuckk Hubbard wrote:
> i*sin(a) and i*sin(b) multiply to -sin(a)sin(b)?
let's forget the sin*sin and look at the i*i part only: since i =
sqrt(-1) by definition, i*i is -1 (slowly: i*i= sqrt(-1)*sqrt(-1) =
sqrt(-1 * -1) = sqrt((-1)^2) = -1)
Thus, i*sin(a) * i*sin(b) = -1 * sin(a)*sin(b)
br, piotr
------------------------------