(1) If the number of TV commercials is I times a day, the sales volume of the product is si(0≤i≤n,).

From the meaning of the question, si = bi = 0si? 1+b2i 1≤i≤n，i∈N*，

So when i=n, Sn = b+(B2+B22++B2n) = b (2? 12n)，

Therefore, the functional relationship between the daily sales volume of products S=b(2 pieces) and the TV advertising volume n (times/day) is s = b (2? 12n)，n∈N*。

(2) from the point of view of the meaning of the question, there is b(2? 12n)≥ 1.9b。

Therefore, in order to increase the sales volume of this product compared with that without TV advertisements, advertisements should be broadcast at least four times a day.