How do you write the series #1/2+1/4+1/8+1/16+...# using sigma notation? Precalculus Series Sums of Geometric Sequences 1 Answer Ratnaker Mehta Jan 30, 2017 #1/2+1/4+1/8+1/16+...# #=1/2^1=1/2^2+1/2^3+1/2^4+...# #=sum_(m=1)^(oo)1/2^m," or, simply, we can say,"# #sum_1^oo1/2^m#. Answer link Related questions What is a sample problem about finding the sum of a geometric sequence? What is the formula for the sum of a geometric sequence? What is a sample problem about finding the sum of a geometric sequence? How do I find the sum of the geometric sequence #3/2#, #3/8#? What is the sum of the geometric sequence 3, 15, 75? What is the sum of the geometric sequence 8, 16, 32? How do I find the sum of the geometric series 8 + 4 + 2 + 1? How do you find the sum of the following infinite geometric series, if it exists. 2 + 1.5 +... How do you find the sum of the first 5 terms of the geometric series: 4+ 16 + 64…? How do you find S20 for the geometric series 4 + 12 + 36 + 108 + …? See all questions in Sums of Geometric Sequences Impact of this question 9175 views around the world You can reuse this answer Creative Commons License