The terms, unu_nun, of a periodic sequence are defined by
u1=5andun+1=10un u_1 = 5 \quad \text{and} \quad u_{n+1} = \frac{10}{u_n} u1=5andun+1=un10Find 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.
231 exam-style questions on WJEC A Level Maths 3.4 Sequences and Series (A-level only), covering 3.4.1 Sequences and Series (A-level only), 3.4.2 Sequences and Series (A-level only), 3.4.3 Sequences and Series (A-level only), 3.4.4 Sequences and Series (A-level only), 3.4.5 Sequences and Series (A-level only), 3.4.6 Sequences and Series (A-level only), and 3.4.7 Sequences and Series (A-level only). Each one has a worked solution and a mark scheme showing where the marks go.