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1.4.9 Geometric sequences and series (A-level only)

Card 1 of 21

How do you test whether a sequence is geometric?

A

It alternates between aaa and −a-a−a, so has no limit.

B

r=4080=12r=\frac{40}{80}=\frac12r=8040​=21​

C

For a convergent geometric series, the sum to infinity is S∞=a1−r\boxed{S_\infty=\frac{a}{1-r}}S∞​=1−ra​​.

D

Check that consecutive non-zero terms have a constant ratio.

Card 1 of 21

1.4.9 Geometric sequences and series (A-level only) Flashcards

  1. A Level
  2. /Maths
  3. /1.4.9 Geometric sequences and series (A-level only)

21 flashcards on OCR A Level Maths 1.4.9 Geometric sequences and series (A-level only): the key formulae, methods and definitions you need to recall for Paper 1, Paper 2 and Paper 3.

Flashcards