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 values of b b\,b and c c\,c are 0.5 and -3.5 respectively.
Show that the sum of the series is 470.
For the sequence un=bn+cu_n=bn+cun=bn+c, show that u21u_{21}u21 is -3.5 times u3u_3u3.
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.