Question

Given the recursive function f(n) = f(n - 1) - 3 ; f(1) = 9 , what would be the first three terms of the sequence ?

Answer 1

The first three terms of sequence are 9 , 6 , 3

Solution:

Given the recursive function f(n) = f(n - 1) - 3

Where f(1) = 9

To find: First three terms of sequence

Substitute n = 2 , n = 3 and n = 4 in given recursive function

When n = 2

f(n) = f(n - 1) - 3

f(2) = f(2 - 1) - 3

f(2) = f(1) - 3

f(2) = 9 - 3 = 6

f(2) = 6

Thus second term is 6

When n = 3

f(3) = f( 3 - 1) - 3

f(3) = f(2) - 3

f(3) = 6 - 3 = 3

f(3) = 3

Thus the third term is 3

When n = 4

f(4) = f( 4 - 1) - 3

f(4) = f(3) - 3

f(4) = 3 - 3

f(4) = 0

Thus the fourth term is 0

Thus first three terms of sequence are 9 , 6 , 3