An arithmetic series has first term a a\,a and common difference ddd.
Prove that the sum of the first n n\,n terms of the series is
12n(2a+(n−1)d) \frac{1}{2}n(2a + (n-1)d) 21n(2a+(n−1)d)Practise Edexcel A Level Maths 3.2 Arithmetic Series with exam-style questions for A Level Maths. 38 questions, matched to the Edexcel A Level Maths (9MA0) specification and written in Paper 1, Paper 2 and Paper 3 style. Every question includes a full worked solution and mark scheme, so you can see where marks are awarded rather than just whether you got the answer right.