plot(fn,-1,1) could be helpful, hth, Ingmar
On 25 Apr 2007, at 09:15, francogrex wrote: > > This below is not solvable with uniroot to find "a": > fn=function(a){ > b=(0.7/a)-a > (1/(a+b+1))-0.0025 > } > uniroot(fn,c(-500,500)) gives > "Error in uniroot(fn, c(-500, 500)) : f() values at end points not of > opposite sign" > > I read R-help posts and someone wrote a function: > http://finzi.psych.upenn.edu/R/Rhelp02a/archive/92407.html > but it is not very precise. Is there any '"standard" function in R > that can > solve this? thanks. > -- > View this message in context: http://www.nabble.com/How-to-solve- > difficult-equations--tf3643595.html#a10175603 > Sent from the R help mailing list archive at Nabble.com. > > ______________________________________________ > R-help@stat.math.ethz.ch 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. Ingmar Visser Department of Psychology, University of Amsterdam Roetersstraat 15 1018 WB Amsterdam The Netherlands t: +31-20-5256735 [[alternative HTML version deleted]] ______________________________________________ R-help@stat.math.ethz.ch 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.