From owner-freebsd-chat@FreeBSD.ORG Mon May 19 04:07:44 2008 Return-Path: Delivered-To: freebsd-chat@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 957F01065674 for ; Mon, 19 May 2008 04:07:44 +0000 (UTC) (envelope-from grog@lemis.com) Received: from ozlabs.org (ozlabs.org [203.10.76.45]) by mx1.freebsd.org (Postfix) with ESMTP id 545148FC23 for ; Mon, 19 May 2008 04:07:44 +0000 (UTC) (envelope-from grog@lemis.com) Received: from dereel.lemis.com (ozlabs.org [203.10.76.45]) by ozlabs.org (Postfix) with ESMTP id 1F89DDDEE0; Mon, 19 May 2008 13:52:14 +1000 (EST) Received: by dereel.lemis.com (Postfix, from userid 1004) id DB7E822AB5; Mon, 19 May 2008 13:52:09 +1000 (EST) Date: Mon, 19 May 2008 13:52:09 +1000 From: Greg 'groggy' Lehey To: Jim Capozzoli Message-ID: <20080519035209.GT46655@dereel.lemis.com> References: <37f72b1f0805181418j16efd60fge243160dbfdc6789@mail.gmail.com> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="KxKI/R+N9hudrWbn" Content-Disposition: inline In-Reply-To: <37f72b1f0805181418j16efd60fge243160dbfdc6789@mail.gmail.com> User-Agent: Mutt/1.4.2.3i Organization: The FreeBSD Project Phone: +61-3-5346-1370 Mobile: +61-418-838-708 WWW-Home-Page: http://www.FreeBSD.org/ X-PGP-Fingerprint: 9A1B 8202 BCCE B846 F92F 09AC 22E6 F290 507A 4223 Cc: freebsd-chat@freebsd.org Subject: Re: slide rules X-BeenThere: freebsd-chat@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Non technical items related to the community List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 19 May 2008 04:07:44 -0000 --KxKI/R+N9hudrWbn Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Sunday, 18 May 2008 at 17:18:30 -0400, Jim Capozzoli wrote: > So, I pulled out the slide rule yesterday that's older then I am..and > I figured out how to multiply/divide on it. Is there anybody out > there still using slide rules for day to day math? Or does anybody > have any interesting stories/reminiscences about slide rules? I was > considering figuring out how to do Trig on it and then taking my Trig > final with it. :) Heh. I don't know where my slide rule is, but it's definitely a lot younger than I am. So the following is from memory. It applies to the conventional slide rules that I know, with C/D scales going from 1 to 10 at the bottom, and A/B scales going from 1 to 100 at the top (giving squares of the corresponding scale below). To multiply two numbers, you place the 1 on the C scale (bottom of the slide) against the first number on the D scale (directly below on the body). Move the cursor (or your eye :-) to the second number on the C scale, and read off the result on the D scale. To divide one number by another, you place the divisor the C scale above the dividend on the D scale. Read off the quotient on the D scale below the 1 on the C scale. Greg -- See complete headers for address and phone numbers. --KxKI/R+N9hudrWbn Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.4 (FreeBSD) iD8DBQFIMPlpIubykFB6QiMRAvOIAKCrWfDNQFG5dk1nN2JauI5Mkk2D8ACgh3b/ AdJVQn2L60Kp3jEd1m5lwv4= =LhMi -----END PGP SIGNATURE----- --KxKI/R+N9hudrWbn--