Which of the following is the explicit formula for the sequence below?

8, 12, 16, 20, ...

A. an = 8 + (n - 1)4
B. an = 8 + 4n
C. an = 4 + (n - 1)8
D. an = 4 + 8n

Question

Which of the following is the explicit formula for the sequence below?

8, 12, 16, 20, ...


 		A.	an = 8 + (n - 1)4
 		B.	an = 8 + 4n
 		C.	an = 4 + (n - 1)8
 		D.	an = 4 + 8n

anonymous · Answer

@amistre64

amistre64 · Answer

start by letting n=1;  which ones equal 8 as a result?

anonymous · Answer

A and B ?

anonymous · Answer

would it be A ?

hartnn · Answer

only A results in 1st term =8, so yes, its A

anonymous · Answer

thank you @hartnn

amistre64 · Answer

B would equal 12 :)

amistre64 · Answer

do you know what your text suggests you start your ns with?  0 or 1?

amistre64 · Answer

8 + 4n

 8 + 4.0 = 8
 8 + 4.1 = 12
 8 + 4.2 = 16
 8 + 4.3 = 20

or ....

 8 + (n - 1)4

 8 + (1 - 1)4 = 8
 8 + (2 - 1)4 = 12
 8 + (3 - 1)4 = 16
 8 + (4 - 1)4 = 20

amistre64 · Answer

so this all depends on what your material defines for the starting point of "n"

anonymous · Answer

thank you ! :) that helps alot !

amistre64 · Answer

good luck :)