Previous in Relation and Functions Next in Relation and Functions
Question Number 94661 by msup by abdo last updated on 20/May/20
$${calculate}\:\Sigma\:{a}_{{n}} {x}^{{n}} \:{if}\:{a}_{{n}} \:{verify} \\ $$$${a}_{{n}+\mathrm{1}} ={a}_{{n}} \:+{a}_{{n}−\mathrm{1}} \\ $$