A start-up company tracks its daily net cash flow, CnC_nCn, in pounds (£\pounds£). The cash flow follows an arithmetic sequence with first term aaa and common difference ddd.
The total net cash flow over the first 12 days is £\pounds£ 432.
Show that 4a+22d=1444a + 22d = 1444a+22d=144.
Given that the total net cash flow over the first 30 days is £\pounds£ 0, determine the total net cash flow over the first 15 days.
SnS_nSn represents the sum of the daily net cash flow for the first nnn days. Explain why the value you calculated in part (b) is the maximum value of SnS_nSn.
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.