function [z, iters] = metsiecznych(a,b, epsilon,max_iter,fnc)
xn = a;
xn1 = b;
i = 0;
x = xn;
fxn = eval(fnc);
x = xn1;
fxn1 = eval(fnc);
z = [xn];
while abs(xn - xn1) > epsilon && i < max_iter,
    i = i + 1;
    xnp1 = xn - (fxn * (xn - xn1)) / (fxn - fxn1);
    xn1 = xn;
    xn = xnp1;
    x = xn;
    fxn = eval(fnc);
    x = xn1;
    fxn1 = eval(fnc);
    z = [z; xnp1];
end
iters = i;