
function [x_min, f_min, x_max, f_max] = Peng522(first_value, last_value, steps, func)
h = abs(last_value-first_value)/steps;

x = first_value:h:last_value;
y = feval(func, x);
plot(x, y);
[f_min, i] = min(y);
[f_max, k] = max(y);
x_min  = x(i); 
x_max = x(k);


