A sequence u1,u2,u3,… u_1, u_2, u_3, \dots\,u1,u2,u3,… is defined by
u1=3u_1 = 3u1=3, u2=5u_2 = 5u2=5
un=un−1+un−2u_n = u_{n-1} + u_{n-2}un=un−1+un−2, n≥3n \geq 3n≥3
Find u3u_3u3, u4 u_4\,u4 and u5u_5u5.
308 exam-style questions on AQA A Level Maths 1.7 D: Sequences and series, covering 1.7.1 Binomial expansion, 1.7.2 Types of sequence (A-level only), 1.7.3 Sigma notation (A-level only), 1.7.4 Arithmetic sequences and series (A-level only), 1.7.5 Geometric sequences and series (A-level only), and 1.7.6 Sequences and series in modelling (A-level only). Each one has a worked solution and a mark scheme showing where the marks go.