sum of following series

saahil's Avatar, Join Date: Aug 2008
Newbie Member
enter x &n and display sum of following series
x1 +x2 +x3+- - - - - - - -+xn(1,2,3,-----,n are powers of x)
asadullah.ansari's Avatar, Join Date: Jan 2008
TechCake
Use this formula...

sum = a |(r^(n-1) -1 )| /|(r-1)|

where a = first term
r = second term/ first term ( Tn/T(n-1) )