An arithmetic series has first term 800 and 5th term 560.
The sum of the first n n\,n terms is denoted by SSS. Show that the 15th term of the series is negative and find the greatest value of S S\,S as n n\,n varies.
326 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.