Is sequences and series on the AQA, Edexcel and OCR A Level Maths exams?
Yes. Sequences and Series is part of the A Level Maths content that every board examines: AQA section D, Edexcel Pure 4, OCR 1.04. It is assessed in AQA Paper 1, and Section A of Papers 2 and 3; Edexcel Paper 1 and Paper 2; OCR A Paper 1, and the pure sections of Papers 2 and 3.
Is sequences and series Year 12 or Year 13 content?
Both. The AS content, usually taught in Year 12, is: The binomial expansion of (a + bx)ⁿ for positive integer n, using nCr and factorial notation. The full A Level adds: The binomial expansion for any rational n and its range of validity; Arithmetic and geometric sequences and series, including sums to infinity; Sigma notation and recurrence relations; increasing, decreasing and periodic sequences; Modelling with sequences and series.
When is a binomial expansion valid?
For positive integer n the expansion is finite and always valid. For negative or fractional n, (1 + bx)ⁿ is valid only when |bx| < 1. Exams often ask you to state this range.