S(n+1)=S(n)+S(n)*.08=S(n)*(1.08)
The students in a year (S(n+1) means students in the current year) is equal to the number of students in the previous year plus .08 times the number of students in the previous year.
In the difference equation we have to know the number of students enrolled in a previous year. A functional equation tells us the students in a given year without knowing the number in the previous year.
is the functional equation with S=# of students and t = number of years that have passed.
When 0 years have passed (1990) 
In 2005 15 years have passed so t=15.
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