The area covered by a species of ground-cover plant has a rate of increase of y cm²/week,
given by: . where is the number of weeks after planting.
According to the model, if the plant covered 100 cm² when planted.
What area will it cover after 4 weeks?
Since is the rate of increase of ground cover,
the amount (area) of ground cover at time is given by:
We are told that, when
So we have: .
Hence, the area function is: .