Question

Which of the following is a geometric sequence?

a. 3, 7, 11, 15, 19
b. 4, 6, 10, 16, 26
c. 4, 16, 64, 256

Answer 1

Hello,

A: is an arithmetic sequence: f(n)=3+(n-1)*4

B: is a Fibbonacci's sequence f(n+2)=f(n+1)+f(n), f(1)=4,f(2)=6

C: is a geometric sequence :first term =4 ratio=4

f(n)=4*4^(n-1)=4^n