Dear All: I submitted this post to the R-sig-Teaching List too I am trying to solve an equation including an integral for unknown parameter. Is this can be done in R? if so, any helps will be highly appreciated ### The following function is a function of t, given exi, nu, and alpha. fun<-function(exi,nu,alpha) (nu+t^2)^(-(nu+1)/2)*exp(((nu+1)*exi*t)/((nu+t^2)^0.5)) ### I want to solve "[Integral(-Inf,100) fun(exi,nu,alpha)]-(1-alpha)=0" for t. ### That is, find the value of t which satisfy the equation: [Integral(-Inf,100) fun(exi,nu,alpha)]-(1-alpha)=0 ### for example given: alpha = 0.05, nu = 20 , exi = 0.5, Solve for t. with many thanks steve -------------------------- Steven M. Stoline 1123 Forest Avenue Portland, ME 04112 sstoline at gmail.com [[alternative HTML version deleted]]