Edexcel FD2 2020 June — Question 4

Exam BoardEdexcel
ModuleFD2 (Further Decision 2)
Year2020
SessionJune
TopicSequences and Series

  1. The complementary function for the second order recurrence relation
$$u _ { n + 2 } + \alpha u _ { n + 1 } + \beta u _ { n } = 20 ( - 3 ) ^ { n } \quad n \geqslant 0$$ is given by $$u _ { n } = A ( 2 ) ^ { n } + B ( - 1 ) ^ { n }$$ where \(A\) and \(B\) are arbitrary non-zero constants.
  1. Find the value of \(\alpha\) and the value of \(\beta\). Given that \(2 u _ { 0 } = u _ { 1 }\) and \(u _ { 4 } = 164\)
  2. find the solution of this second order recurrence relation to obtain an expression for \(u _ { n }\) in terms of \(n\).
    (6)