###############################################
#Modified From the uniroot help file of S-Plus
##############################################


#####First, create a general cubic whose root will be known (since we supply them!)

cubic <- function(x, c2, c1, c0) {(x - c2) * (x - c1) * (x - c0)} 

#####Now test uniroot one out example with specific values of the roots:

uniroot(cubic, c(1,3), keep.xy=T, c2=-2, c1=0, c0=2) 


#####Now a more elaborate (incrutable?) version of cubic:

cubic <- function(x, c2, c1, c0, nf=0, 
                  all=list(x=NULL, y=NULL)) {
value <- (x - c0) * (x - c1) * (x - c2) 
attributes(value) <- list(nf=nf + length(x), 
      all=list(x=c(all$x, x), y=c(all$y, value)))
value } 


######And a test of the solver


uniroot(cubic, lower=1, upper=3, c2=-2, c1=0, c0=2) 

#########################################
#Related Functions:
##########################################
 
nlregb , 
optimize , 
polyroot,
nlmin.