2. A recursive function is shown below: f(1) = 2 and f(n) = f(n – 1) – 5; n 1
Which of the following lists the terms in the sequence defined by this recursive function?
A. 2, 3, 8, 13, 18, ...
B. 2, 7, 12, 17, 22, ...
C. 2, –3, –8, –13, –18, ...
D. 2, –7, –12, –17, –22, ...

Question

2. A recursive function is shown below: f(1) = 2 and f(n) = f(n – 1) – 5; n > 1 
 Which of the following lists the terms in the sequence defined by this recursive function? 
 A. 2, 3, 8, 13, 18, ... 
 B. 2, 7, 12, 17, 22, ... 
 C. 2, –3, –8, –13, –18, ... 
 D. 2, –7, –12, –17, –22, ...

ranga · Answer

f(n) = f(n – 1) – 5 
The way to read this recursive formula is:
current term = previous term minus 5.
Which sequence has the number 5 subtracted each time?

ranga · Answer

Look at the second number in each sequence.  
Does the second term equal the first term minus 5?

anonymous · Answer

@ your first statement: B
@ your second statement: B, it does.

ranga · Answer

No.  B adds 5 each time.
We are looking for subtraction of  5 each time.

anonymous · Answer

Oh, then it has to be:

C, because 2 - 5 = -3, and so on.

ranga · Answer

yes.

anonymous · Answer

So it would be C?