Assume that the cost, in thousands of dollars, of airingxtelevision commercials during a sports event is given by

C(x) = 20 +4,800x+0.03x².

completed >(a) Find the marginal cost function.

C'(x) = 4800+0.06x

Use it to estimate how fast the cost (in thousands of dollars) is increasing when

x= 4.

completed> 4824 thousand dollars per television commercial

Compare this with the exact cost (in dollars) of airing the fifth commercial.

The cost is going up at the rate of$ _________ per television commercial.The exact cost of airing the fifth commercial is$________ .Thus, there is a difference of$_________ .

(b)Find the average cost function C, and evaluate C(4) (in thousands of dollars).

C(x)=_____

C(4)=__________ thousand dollars per television commercial

What does the answer tell you?

The average cost of airing the first four commercials is $ __________ per commercial.