Determine the common ration of the infinite geometric series:
1. a1 = 1, S = 1.25
2. a1 = 96, S = 64
3. a1 = 4, S = -16/5
4. a1 = 1, S = 2.5
Accepted Solution
A:
Sum of geometric series formula: $$ S=\frac{a1}{1-r} $$ Since r is the common ratio: $$ r=\frac{S-a1}{S} $$ Substitute the given:
1. r = 0.2
2. r = -0.5
3. r = 2.25
4. r = 0.6