Question

A sequence is defined by the recursive function f(n + 1) =1/3 f(n). if f(3) 9= , what is f(1)

Answer 1

f(1) = 81

Explanation:

f(n + 1) = 1/3 f(n)

⇔ f(n) = 3 × f(n + 1)

……………………………

if f(3) = 9 ⇒ f(2) = 3 × f(3) = 3 × 9 = 27

Then

f(1) = 3 × f(2) = 3 × 27 = 81