# summation notation

• Nov 26th 2006, 09:43 PM
checkeredshawn
summation notation
Hi, I'm having trouble turning this summation notation into a function, any help would be greatly appreciated. Thank you.
http://minerva.ccs.neu.edu/cgi-bin/C...s/sumtoinf.gif (1/5)^k
• Nov 26th 2006, 10:31 PM
earboth
Quote:

Originally Posted by checkeredshawn
Hi, I'm having trouble turning this summation notation into a function, any help would be greatly appreciated. Thank you.
http://minerva.ccs.neu.edu/cgi-bin/C...s/sumtoinf.gif (1/5)^k

Hello,

what you describe is one value because the infinite geometric serie is convergent. The limes can be calcutated:

$s=\frac{a_1}{1-q}$.
With your problem $a_1=\frac{1}{5}\text{ and }q=\frac{1}{5}$. Plug in these values:

$s=\frac{\frac{1}{5}}{1-\frac{1}{5}}=\frac{1}{4}$.

EB