Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.2 9/18/84; site brl-tgr.ARPA Path: utzoo!linus!philabs!cmcl2!seismo!brl-tgr!gwyn From: gwyn@brl-tgr.ARPA (Doug Gwyn) Newsgroups: net.graphics Subject: Re: Dithering and a project Message-ID: <5404@brl-tgr.ARPA> Date: Fri, 19-Oct-84 21:08:25 EDT Article-I.D.: brl-tgr.5404 Posted: Fri Oct 19 21:08:25 1984 Date-Received: Sat, 20-Oct-84 07:37:57 EDT References: <1556@ucla-cs.ARPA> <16648@arizona.UUCP> Organization: Ballistic Research Lab Lines: 10 > I need a quick way to determine the solution for z of > A*z^2 + B*z*x + C*z + D*x^2 + E*x + F >= 0 > at (x+1), given the solution at x. "Quick" means faster than substituting > the new x value and solving directly. (You must mean = 0, not >= 0.) Sorry, Roger, after cleaning up the statement of the problem, I find that you must solve a quadratic equation no matter what. The best you can do is to take some shortcuts in evaluating the coefficients of the quadratic.