Answer:
f(3) = 1
Explanation:
We have been given:
f(1) = 25
f(n) = f(n-1) · (-1/5)
Find f(2) by substituting n=2 in the given equation:
f(n) = f(n-1) · (-1/5)
f(2) = f(2-1) · (-1/5)
f(2) = f(1) · (-1/5)
where f(1) given in the question is 25, substitute it in the equation
f(2) = 25 · (-1/5)
f(2) = -5
Find f(3) by substituting n=3 in the given equation
f(n) = f(n-1) · (-1/5)
f(3) = f(3-1) · (-1/5)
f(3) = f(2) · (-1/5)
where f(2) found in the previous step was -5, substitute it in the equation.
f(3) = -5 · (-1/5)
f(3) = 1