# recursion formula's

• January 11th 2006, 01:16 PM
mondo425
recursion formula's
Can you write the recursion formula for this series? $a_n=\frac{1}{2^n}$ :confused:
• January 11th 2006, 01:47 PM
CaptainBlack
You give:

$a_n=\frac{1}{2^n}$.

This as it stands is a sequence not a series, and

$a_{n+1}=\frac{1}{2^{n+1}}=\frac{1}{2^n.2}=\frac{1} {2}a_n$.

RonL