Using function concepts, it is found that the turning points of the graph are:
- November 2000, when it goes from increasing to decreasing.
- December 2000, when it goes from decreasing to increasing.
- June 2001, when it goes from increasing to decreasing.
In a graph:
- A function is increasing if it is pointing upwards.
- If it is pointing downwards, it is decreasing.
- A turning point is when the function changes from decreasing to increasing or vice-versa.
In this problem:
- Initially, the function is increasing.
- In month 3, that is, November 2000, it starts to decrease, thus, in November 2000, we have a turning point.
- The next month, that is, December 2000, it starts to increase again, so it is another turning point.
- It increases until month 9, which is June 2001, when it starts to decrease, being the final turning point.
A similar problem is given at https://brainly.com/question/13539822
