The function is , where is the year and is the model.

(a)

Find .

Substitute in .

.

The sales for the first year is million.

Find .

Substitute in .

.

The sales for the fifth year ismillion.

(b)

 I think the model is the more accurate for the later years.

From part (a), .

From the given data .

gives an estimate that is times the amount of the actual sales value.

And

From the given data, .

gives an estimate that is times the amount of the actual sales value.

The model is the more accurate for the later years.

(a). and .

(b). The model is the more accurate for the later years.