def trapets integr for in integr call end integr call call end

def trapets(n)
        integr = 0.0;
        h = (@b - @a)/n;
        for i in 1 .. (n - 1)
            integr += @f.call(@a + h * i);
        end
        (integr + (@f.call(@a) + @f.call(@b))/2) * h
    end