Question

A sequence has an initial value of 10 and each term is twice the previous.  Which function models this sequence?

Answer 1

$10,\ 20,\ 40,\ 80,\ ...\\\\a_n=2\cdot a_{n-1}\ \ \ \Rightarrow\ \ \ q=2\\\\geometric\ sequence \ \ \ \Rightarrow\ \ \ a_n=a_1\cdot q^{n-1}\\\\a_1=10\ \ \ and\ \ \ q=2 \ \ \ \Rightarrow\ \ \ a_n=10\cdot 2^{n-1}\\\\Ans.\ this\ sequence\ models:\ \ \ a_n=10\cdot 2^{n-1}$