Skip to content
MathsGenie logo
Open app

Course home

  1. A Level
  3. Maths CCEA
  5. Question bank

Sequences and Series

EasyMedium
123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384
Question 60

The second term of a geometric series is 3.75 and the sum to infinity is 20.

a.

Find the two possible values of rrr.

[4]
b.

Find the corresponding two possible values of aaa.

[2]
c.

Given that r r\,r takes the larger of the two possible values, find the smallest value of n n\,n for which Sn>19S_n > 19Sn​>19.

[4]

Sequences and Series Questions

  1. A Level
  2. /Maths
  3. /Sequences and Series