9 An analyst believes that the sales of a particular electronic device are growing exponentially. In 2015 the sales were 3.1 million devices and the rate of increase in the annual sales is 0.8 million devices per year.
- Find a model to represent the annual sales, defining any variables used.
- In 2017 the sales were 5.2 million devices. Determine whether this is consistent with the model in part (i).
- The analyst uses the model in part (i) to predict the sales for 2025. Comment on the reliability of this prediction.