From mboxrd@z Thu Jan 1 00:00:00 1970 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on inbox.vuxu.org X-Spam-Level: X-Spam-Status: No, score=-1.0 required=5.0 tests=MAILING_LIST_MULTI, RCVD_IN_DNSWL_NONE autolearn=ham autolearn_force=no version=3.4.4 Received: (qmail 4635 invoked from network); 13 Sep 2020 15:53:12 -0000 Received: from minnie.tuhs.org (45.79.103.53) by inbox.vuxu.org with ESMTPUTF8; 13 Sep 2020 15:53:12 -0000 Received: by minnie.tuhs.org (Postfix, from userid 112) id 4E9379C78F; Mon, 14 Sep 2020 01:53:08 +1000 (AEST) Received: from minnie.tuhs.org (localhost [127.0.0.1]) by minnie.tuhs.org (Postfix) with ESMTP id 41D109C6B4; Mon, 14 Sep 2020 01:52:28 +1000 (AEST) Received: by minnie.tuhs.org (Postfix, from userid 112) id A1DA09C6B4; Mon, 14 Sep 2020 01:52:24 +1000 (AEST) X-Greylist: delayed 444 seconds by postgrey-1.36 at minnie.tuhs.org; Mon, 14 Sep 2020 01:52:23 AEST Received: from w21.org (oluf.w21.org [85.214.246.193]) by minnie.tuhs.org (Postfix) with ESMTPS id AF8239C6AE for ; Mon, 14 Sep 2020 01:52:23 +1000 (AEST) Received: by w21.org (Postfix, from userid 9) id 7982728E004A; Sun, 13 Sep 2020 17:44:57 +0200 (CEST) To: tuhs@tuhs.org From: Juergen Nickelsen Newsgroups: w21.lists.tuhs Date: Sun, 13 Sep 2020 17:44:57 +0200 Organization: W21 Distribution: w21 Message-ID: <87tuw1n0jq.fsf@lith.ni.w21.org> References: <20200320140308.4FBBB18C073@mercury.lcs.mit.edu> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/25.1 (darwin) Cancel-Lock: sha1:YTliYTFmMzA1NjNhOTM0NzQ4Y2FlZDcxMjk2MDAxY2NlNWU5ZGEzMg== Subject: Re: [TUHS] The most surprising Unix programs X-BeenThere: tuhs@minnie.tuhs.org X-Mailman-Version: 2.1.26 Precedence: list List-Id: The Unix Heritage Society mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: tuhs-bounces@minnie.tuhs.org Sender: "TUHS" Grant Taylor via TUHS writes: > For example, let's start with Pythagorean Theorem > > a² + b² = c² [...] > [a] [enter] > [a] [enter] > [multiply] > [b] [enter] > [b] [enter] > [multiply] > [add] > [square root] # to solve for c I do [a] [square] [b] [square] [plus] [square root] 6 keys. (Many operations push the entered value into the x register without needing the enter key. Also, like with infix calculators, usually there is a [x^2] key -- in postfix notation on both!) > [a] > [square] > [plus] > [b] > [square] > [square root] That would give you the value of [b] and leave some rest of the operation in the (hidden) registers. Actually you need [a] [square] [plus] [b] [square] [=] [square root] 7 keys. Although I started with infix calculators, I find it easier to work my way out of more complex nested formulas with RPN than to track the level of parentheses in my mind. Consider something like this: 3y * x / (z + 4k)^2 2w + v! \ ------ * | ---------- + ---------- | 5b + z \ 3b * 4x ln(x + 2y) / Now this is a PITA either way, but it comes easier for me with RPN. [Sorry for the late reply -- I subscribed to TUHS earlier this year and am only now making my way through it.] -- Kein Wunder, wenn bei Leuten, die tagaus, tagein Zugriff auf alles haben, was die Welt im Internet anbietet, die Fantasie-Sicherungen durchbrennen. -- Karl Notter