Suppose that a company's daily sales volume attributed to an advertising campaign is given by the following equation. 45 S(t) = _ 9 + 6 t+ 8 (t + 8) 2 (a) Find how long it will be before sales volume is maximized. t = days (b) Find how long it will be before the rate of change of sales volume is minimized. That is, find the point of diminishing returns. t = days