1. function y=f(x)
y=2*x**3+x-1;
endfunction
function y=df(x)
y=6*x**2+1;
endfunction
function x=newtonraphson(x0,tol);
i=1;
ea(1)=100;
x(1)=x0;
while abs(ea(i))>=tol;
x(i+1)=x(i)-f(x(i))/df(x(i));
ea(i+1)=abs((x(i+1)-x(i))/x(i+1));
i=i+1;
end
printf(' i t X(i) Error aprox (i) n');
for j=1:i;
printf('%2d t %11.7f t %7.6f n',j-1,x(j),ea(j));
end
endfunction