+0  
 
0
43
1
avatar

Find an explicit formula for the geometric sequence with  a2=12  and a4=48

 May 7, 2021
 #1
avatar
0

First thing I see is that we can take 12 out of both of them, that's helpful.

a2 is 1, a4 is 4.

 

2^0 is 1, and 2^2 is 4, that's a helpful fact... but our subscripts were 2 and 4, not 0 and 2. We could shift them by using 2^(x - 2). Thus:

 

\(12 * 2^{x-2}\)

 

I suppose 2^x * 2^-2 is basically 2^x / 4, so we could simplify further to:

 

\(3 * 2^{x}\)

 May 7, 2021

17 Online Users

avatar
avatar