Sum of an infinite GP
Sequences, series and the binomial theorem · Mathematics
Study notes
Q: Find the infinite sum: (a) 1 + 1/2 + 1/4 + ... (b) 9 + 3 + 1 + 1/3 + ... (a) a = 1, r = 1/2. S∞ = 1/(1 - 1/2) = 1/(1/2) = 2. (b) a = 9, r = 1/3. S∞ = 9/(1 - 1/3) = 9/(2/3) = 13.5.