The terms, unu_nun, of a periodic sequence are defined by
u1=5andun+1=10unu_1 = 5 \quad \text{and} \quad u_{n+1} = \frac{10}{u_n}u1=5andun+1=un10
Find u2u_2u2, u3u_3u3 and u4u_4u4.
State the period of the sequence.
Find the value of ∑n=151un\sum_{n=1}^{51} u_n∑n=151un.
Practise Edexcel A Level Maths Sequences and Series with exam-style questions for A Level Maths. 100 questions covering 3.1 Arithmetic Sequences, 3.2 Arithmetic Series, 3.3 Geometric Sequences, 3.4 Geometric Series, 3.5 Sum to Infinity, 3.6 Sigma Notation, 3.7 Recurrence Relations, and 3.8 Modelling with Series, matched to the Edexcel A Level Maths (9MA0) specification and written in Paper 1, Paper 2 and Paper 3 style. Every question includes a full worked solution and mark scheme, so you can see where marks are awarded rather than just whether you got the answer right.