Example of recursion in R

newton_recursive.R

#Example of using recursion to apply newton's method to an arbitrary function in order to find the zeros of the function. If no zeros are found after some number of iterations, NA is returned

newton.recursive<-function(func,deriv,counter=100,x=1,relchange=1){
    diff = func(x)/deriv(x)
    relchange = abs(diff/x)
    if(counter==0){
      print("Failed to converge")
      return(NA)
    }
    else if(relchange <= 1e-10){
      return(x)
    }
    else{
      return(newton.recursive(func,deriv,counter=counter-1,x=x-diff,relchange))
    }
}