Answer:
[tex]y=1500\cdot(0.902)^T[/tex]
Step-by-step explanation:
Let T be the number of years since the start of the study and y be the area that the forest covers in [tex]\text{km}^2[/tex].
We have been given that at the beginning of an environmental study a forest cover an area of 1500 [tex]\text{km}^2[/tex]. Since then this area has decreased by 9.8% each year.
We know that an exponential function is in form [tex]y=a\cdot(1-r)^x[/tex], where,
y = Final amount,
a = Initial amount,
r = Decay rate in decimal form,
x = Time.
Let us convert 9.8% into decimal as:
[tex]9.8\%=\frac{9.8}{100}=0.098[/tex]
We have been given that initial value (a) is [tex]1500[/tex].
Upon substituting our given values, we will get:
[tex]y=1500\cdot(1-0.098)^T[/tex]
[tex]y=1500\cdot(0.902)^T[/tex]
Therefore, our required exponential function would be [tex]y=1500\cdot(0.902)^T[/tex].