Path: csiph.com!x330-a1.tempe.blueboxinc.net!usenet.pasdenom.info!gegeweb.org!de-l.enfer-du-nord.net!feeder2.enfer-du-nord.net!feeder.news-service.com!newspump.sol.net!posts.news.twtelecom.net!nnrp2.twtelecom.net!not-for-mail From: DrMajorBob Newsgroups: comp.soft-sys.math.mathematica Subject: Re: How can I write the input code for a comparison Date: Sun, 26 Jun 2011 10:30:31 +0000 (UTC) Organization: Steven M. Christensen and Associates, Inc and MathTensor, Inc. Sender: steve@smc.vnet.net Approved: Steven M. Christensen , Moderator Message-ID: References: <201106250928.FAA20187@smc.vnet.net> Reply-To: drmajorbob@yahoo.com Lines: 34 NNTP-Posting-Date: 26 Jun 2011 09:31:59 GMT NNTP-Posting-Host: 15067269.news.twtelecom.net X-Trace: DXC=268dDF>RI_lE0G1fKX\WG`C_A=>8kQj6m9BHNOcEA\@iZRLT<^dY1gjEFiONJ7[GofhgY>d?aUd;c X-Complaints-To: abuse@twtelecom.net Xref: x330-a1.tempe.blueboxinc.net comp.soft-sys.math.mathematica:3313 m > n is not always true, since: m = (6 + 4 R + B^2 R - 5 R^2 - R^3 + R^4 + B (R^2 + R - 2)); n = (6 + 4 r + k^2 r - 5 r^2 - r^3 + r^4 + k (r^2 + r - 2)); condition = {0 < r < R < 1, 0 < k < B < 1}; FindInstance[Flatten@{m < n, condition}, {r, R, k, B}, Reals] {{r -> 1/64, R -> 283/16384, k -> 1/4, B -> 513/1024}} Bobby On Sat, 25 Jun 2011 04:28:00 -0500, Nan wrote: > Sorry for the notation misusage problem in my previous post, it should > be: > > I need to compare M with N > M=(6+4R+B^2 R-5R^2-R^3+R^4+B(R^2+R-2)) > N=(6+4r+k^2 r-5r^2-r^3+r^4+k(r^2+r-2)), > where 0 < r < R < 1, 0 < k < B < 1. > > Notice that M and N have same form of functions but with different > variables. Actually I need to prove that they have certain relationship, > say M>N. How can I do that by Mathematica? Can I use MinValue or > FindMinvalue? That is, if the minimum value of M - N >0, then M > N. How > can I write the input command so that I can include the constraint? > Please help! Thanks a lot! > -- DrMajorBob@yahoo.com