Question

Write the formula for the geometric sequence.
7, 21, 63, 189…
A. an=7∙3n-1
B. an=189∙3n-1
C. an=7∙3n
D. an=

Answer 1

An=7*(3^n) because if n=0 you get just 7, if n=1 you get 7*3, aka 21, etc

Answer 2

need more clarification?

Answer 3

Just multiply by 3:

7, 21, 63, 189, 567, 1701, 5103...

The general formula for the geometric sequence is:

a(n) = 7*3^(n-1)

So it's A.)

Answer 4

opps yea, that's the one^

Answer 5

Haah lol I do tht all the time 2! lol :p @sschroeder

Answer 6

i guess it differs depending on what value of N you want to start with, they do the same action but for the one i selected it means N=0 is the start, where as yours would start at n=1... I still think mine should be right

Now that i look at it more

Answer 7

thank you :)

Answer 8

I seriously feel like it's actually C not A, assuming you would always start with an n=0 value, but it all depends, they do the same thing. does is define what n starts as?

Answer 9

Ohh ya ur rite srry i accidently did a typo.... It's c.) My answer can prove it.. Srry @sschroeder and @ashleyhelget

Answer 10

no worries, thank you again

Answer 11

Cuz if u distribute the 1 its going to stay a 3.. So therefore it's C.)

Answer 12

Answer: C.)