function sum (xlow, xhigh, eps)
%метод центральных прямоугольников

n = 2;
h = (xhigh-xlow)/n;
Itstop = 0;
Inprev = 0;
while (Itstop ~= 1);
S = 0;
for k=1:1:n
x = xlow+k*h-h/2;
S = S + funAr1(x);
end
Integral1 = S*h;
if (abs(Integral1 - Inprev)<eps)
Itstop = 1;
else
n = n*2;
h = h/2;
Inprev = Integral1;
end
end
Integral1=2*pi*Integral1;

%метод центральных прямоугольников
n = 2;
h = (xhigh-xlow)/n;
Itstop = 0;
Inprev = 0;
while (Itstop ~= 1);
S = 0;
for k=1:1:n
x = xlow+k*h-h/2;
S = S + funAr(x);
end
Integral2 = S*h;
if (abs(Integral2 - Inprev)<eps)
Itstop = 1;
else
n = n*2;
h = h/2;
Inprev = Integral2;
end
end
Integral2=2*pi*Integral2;

end