function area = demoTrapecio()
    deff('y=f(x)','y=1/x'); 
    n=6;
    b=4;
    a=1;
    area=0; 
    h=(b-a)/n;
    area=f(a);
    for i=1:n-1
       a=a+h; 
       area=area+2*f(a);
    end
    area=area+f(b);
    area=area*(h/2);
endfunction