OCR MEI C4 — Question 6 4 marks

Exam BoardOCR MEI
ModuleC4 (Core Mathematics 4)
Marks4
PaperDownload PDF ↗
TopicSequences and series, recurrence and convergence
TypeRecurrence relation solving for closed form
DifficultyChallenging +1.2 This is a standard recurrence relation convergence problem requiring students to assume a_n+1/a_n → L, substitute into the recurrence to get L = 2 + 3/L, then solve the resulting quadratic. While it requires understanding of limits and algebraic manipulation, it's a well-practiced technique with clear steps and no novel insight needed. The 4 marks reflect routine application of a taught method.
Spec1.04e Sequences: nth term and recurrence relations

6 A sequence is defined by $$a _ { n + 1 } = 2 a _ { n } + 3 a _ { n - 1 } \quad \text { with } a _ { 1 } = 1 \text { and } a _ { 2 } = 1 .$$ Using the method on page 5, show that the value to which the ratio of successive terms converges is 3 .
[0pt] [4]

6 A sequence is defined by

$$a _ { n + 1 } = 2 a _ { n } + 3 a _ { n - 1 } \quad \text { with } a _ { 1 } = 1 \text { and } a _ { 2 } = 1 .$$

Using the method on page 5, show that the value to which the ratio of successive terms converges is 3 .\\[0pt]
[4]\\

\hfill \mbox{\textit{OCR MEI C4  Q6 [4]}}