An arithmetic series is given by ∑n=1150(bn+c)\sum_{n=11}^{50} (bn+c)∑n=1150(bn+c) where b b\,b and c c\,c are constants. The sum of the series is 470.
Show that 122b+4c=47122b + 4c = 47122b+4c=47.
Given the 21st term is 4 times the 3rd term, find the values of b b\,b and ccc.
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.