OP is asking about a system of fourth-order "differential" equations, whereas you are telling her how to solve a single, algebraic nonlinear equation.
Take a look at package "deSolve", and the function `lsode' in that package for solving a system of nonlinear ODEs (given initial values). Ravi. ------------------------------------------------------- Ravi Varadhan, Ph.D. Assistant Professor, Division of Geriatric Medicine and Gerontology School of Medicine Johns Hopkins University Ph. (410) 502-2619 email: rvarad...@jhmi.edu -----Original Message----- From: r-help-boun...@r-project.org [mailto:r-help-boun...@r-project.org] On Behalf Of Wu Gong Sent: Sunday, November 28, 2010 6:31 PM To: r-help@r-project.org Subject: Re: [R] non-linear fourth-order differential equations Hi Yanika, Please try ?uniroot and ?ployroot f <- function(x) x^4-16 uniroot(f, lower= -3, upper=0) polyroot(c(-16,0,0,0,1)) ----- A R learner. -- View this message in context: http://r.789695.n4.nabble.com/non-linear-fourth-order-differential-equations -tp3062805p3062894.html Sent from the R help mailing list archive at Nabble.com. ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code. ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
