A sequence u1,u2,u3,… u_1, u_2, u_3, \dots\,u1,u2,u3,… is defined by
u1=−1un+1=un2−1,n≥1 \begin{aligned}u_1 &= -1 \\u_{n+1} &= u_n^2 - 1, \quad n \geq 1\end{aligned} u1un+1=−1=un2−1,n≥1Find u2,u3 u_2, u_3\,u2,u3 and u4u_4u4.
Write down the value of u100u_{100}u100.
178 exam-style questions on Edexcel A Level Maths Sequences and Series, 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. Each one has a worked solution and a mark scheme showing where the marks go.