Question

Find the sum of the infinite series 1/3+1/9+1/27+... if it exists

Answer 1

this is a GS where
a = 1/3
r =1/3

sum(infinite # of terms) = a/(1-r)
= (1/3)/(1 - 1/3)
= (1/3) / (2/3)
= (1/3)(3/2)
= 1/2