dla pana Marcina

clc;
close;
clear;
tic;
f=@(x)sin(x);
a=-pi;
b=pi;
w=a:0.01:b;
plot(w, f(w));
hold on
line([a,b],[0,0],'color','k')
quad(f,a,b);
x=rand;
h=1;
s=0;
n=floor((b-a)/h);
for i=0:n-1
        s=s+f(a+h+i*h);
        line([a+i*h,a+i*h],[0,f(a+i*h)])
        line([a+i*h,a+(i+1)*h],[f(a+i*h),f(a+(i+1)*h)])
        line([a+(i+1)*h,a+(i+1)*h],[0,f(a+(i+1)*h)])
end
s=(s+(f(a+h)+f(a))/2)*n;
   disp(s);
toc;