The amount of commission...
The amount of commission earned by an online brokerage in a month C,(in hundreds of dollars) is a function of online advertising expenditure, a (in hundreds of dollars) so we write C=f(a).
a.What does the brokerage hope is true about the sign of f' (positive or negative).Why?
b.What does the statement f'(12)=1.4 mean in terms of advertising and commission?
c.Suppose that the company plans to spend about $1200 on advertising.If f'(12)=1.4, then should the company spend more or less on advertising?