Question

For a sequence defined by f(1)=13 and 2f(n-1)+(n-2), which of the following is the value of f(4)

(1) 53
(2) 76
(3) 108
(4) 126

Answer 1

Given that:
f(1)=13 and 2f(n-1)+(n-2)
then:
f(4) will be found as follows:
f(2)=2f(2-1)=2f(1)=2*13=26
f(3)=2f(3-1)+(3-2)=2f(2)+1=2*26+1=53
f(4)=2f(4-1)+(4-2)=2f(3)+(4-2)=2(53)+2=108

Thus:
Answer:(3) 108