format long
x1=2;
x2=1.8;
tol=1e-8;
err=1;
while (err>tol)
fx1=x1^3+4*x1^2-10;
fx2=x2^3+4*x2^2-10;
slope=(fx1-fx2)/(x1-x2);
x3=x2-fx2/slope
x1=x2;
x2=x3;
err=abs((x2-x1)/x2)*100;
end
root=x3