Some of the authors believe that nowadays, with the rapid advancement in the electronic industry, the demand for books has become a lot low. Many people have lost interest in reading on the whole, while others just read them online. Due to this, the publishing of books has been greatly affected. Many writers have quit writing as the profession does not provide much money or respect nowadays.
However, other authors believe that their is still hope in the future of books and publishers. If the books are interesting, people will be forced to buy it for keeping a copy of the book.
Turning point of a graph is the point where the graph where the graph changes from increasing to decreasing (rising to falling) or decreasing to increasing (falling to rising). For a cubic function, the critical point also serves as a turning point.