sum = 0;%the sumn n = 2;%the number of intervals\ pi = 3.141592654; a = (10^-10)/pi;%lower limit b = 1/(2*pi);%upper limit I = .022560661746;%the real integral value for n = 2:2*n:256 for x = a:(b-a)./n:b f = sin(1./x);%the function if x == a sum = sum + f./2; end if x == b sum = sum + f./2; end if x > a && x < b sum = sum + f; end end T = sum.*(b-a)./n; Error = I - T; hold on loglog(abs(Error), (b-a)./n,'.') end