function [p0,err,k,y]=newton(f,df,p0,delta,epsilon,max1)%Input - f is the object function input as a string 'f'%      - df is the derivative of f input as a string 'df'%      - p0 is the initial approximation to a zero of f%	    - delta is the tolerance for p0%	    - epsilon is the tolerance for the function values y%	    - max1 is the maximum number of iterations%Output - p0 is the Newton-Raphson approximation to the zero%	     - err is the error estimate for p0%	     - k is the number of iterations%	     - y is the function value f(p0)%  NUMERICAL METHODS: Matlab Programs% (c) 2004 by John H. Mathews and Kurtis D. Fink%  Complementary Software to accompany the textbook:%  NUMERICAL METHODS: Using Matlab, Fourth Edition%  ISBN: 0-13-065248-2%  Prentice-Hall Pub. Inc.%  One Lake Street%  Upper Saddle River, NJ 07458for k=1:max1		p1=p0-feval(f,p0)/feval(df,p0);		err=abs(p1-p0);	relerr=2*err/(abs(p1)+delta);	p0=p1;	y=feval(f,p0);	if (err<delta)|(relerr<delta)|(abs(y)<epsilon),break,endend