The Inquiry Club at Jefferson University has compiled a book which exposes the sordid private lives of many of the professors on campus. Economics majors in the club estimate total revenue from sales of the book is given by the equation:
TR = 120Q -0.1Q³
a. Over what range of sales is demand elastic?
b. Initially, the price is set at $71.60. To maximize total revenue, should the price be increased or decreased? Explain.