# [PD] basic DSP stuff

Mon Nov 7 22:48:23 CET 2005

``` 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 at majdak.com>
> Subject: Re: [PD] basic DSP stuff
> Cc: Pure Data List <pd-list at iem.at>
> Message-ID: <436FB1EC.80908 at 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
>
>
>
> ------------------------------
>
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