%% Homework Set 9

%% Problem 1: Script file that performs Newton's Method

f=inline('x-exp(-x)');  df=inline('1+exp(-x)');

x(1)=-1;

for j=1:100
  y(j)=f(x(j));
  dy(j)=df(x(j));
  x(j+1)=x(j)-y(j)/dy(j);
  
  if abs(y(j))<10^(-6)
     break;
  end

end

N=length(x);
plot(1:N,x,'^-',1:N-1,y,'*-');

%% Problem 2:  Find the line of best fit using the data below
clear
x=[-1,1,2,3]';  y=[-1,1,1,2]';
A=[x, ones(4,1)];
c=linsolve(A,y)
t=linspace(-1,3);
z=c(1)*t+c(2);
plot(x,y,'*',t,z);