There was a mistake in the previously sent function. I had hard coded the values of parameters `nu' and `exi'.
Use this one: myroot <- function(t, nu, exi, alpha){ fun <- function(t, exi, nu) (nu+t^2)^(-(nu+1)/2)*exp(((nu+1)*exi*t)/((nu+t^2)^0.5)) res <- alpha - integrate(fun, -Inf, t, nu=nu, exi=exi)$value return(res) } uniroot(myroot, c(-2, 2), nu=2, exi=0.5, alpha=.05) Ravi From: Ravi Varadhan Sent: Friday, January 08, 2016 11:29 AM To: r-help@r-project.org; 'sstol...@gmail.com' <sstol...@gmail.com> Subject: Re: Solve an equation including integral I think this is what you want: myroot <- function(t, nu, exi, alpha){ fun <- function(t, exi, nu) (nu+t^2)^(-(nu+1)/2)*exp(((nu+1)*exi*t)/((nu+t^2)^0.5)) res <- alpha - integrate(fun, -Inf, t, nu=2, exi=0.5)$value return(res) } uniroot(myroot, c(-2, 2), nu=2, exi=0.5, alpha=.05) Hope this is helpful, Ravi Ravi Varadhan, Ph.D. (Biostatistics), Ph.D. (Environmental Engg) Associate Professor, Department of Oncology Division of Biostatistics & Bionformatics Sidney Kimmel Comprehensive Cancer Center Johns Hopkins University 550 N. Broadway, Suite 1111-E Baltimore, MD 21205 410-502-2619 [[alternative HTML version deleted]] ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see 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.