# How do you write a rule for the nth term of the geometric sequence, then find a6 given 5, -5/3, 5/9, -5/27, ...?

##### 1 Answer

Jun 6, 2017

#### Explanation:

#"for the standard geometric sequence"#

#a,ar,ar^2,...... ,ar^(n-1)larr" nth term"#

#"where " a=a_1" and r is the common ratio"#

#r=(a_2)/(a_1)=(a_3)/(a_2)= .... =(a_n)/(a_(n+1))#

#rArrr=(-5/3)/5=-1/3#

#rArra_n=ar^(n-1)=5(-1/3)^5larr" nth term rule"#

#rArra_6=5xx-1/243=-5/243#