The demand function for a product is given by p = 4000/In(x + 10) where p is the price per unit in dollars when x units are demanded. (a) Find the rate of change of price with respect to the number of units sold when 40 units are sold. (Round your answer to the nearest cent.) $ (b) Find the rate of change of price with respect to the number of units sold when 90 units are sold. (Round your answer to the nearest cent.) $ (c) Find the second derivative. p"'(x) = 4000(2 + In(x + 10/(x + 10^2(In(x + 10))^3 Is the rate at which the price is changing at 40 units increasing or decreasing? p'(x) is increasing at 40 units. p'(x) is decreasing at 40 units