An arithmetic sequence has first term aaa and common difference ddd.
The sum of the first 9 terms of the sequence is equal to the square of the sum of the first 3 terms.
Show that a+4d=a2+2ad+d2a + 4d = a^2 + 2ad + d^2a+4d=a2+2ad+d2
Given that the fifth term of the sequence is 9, find the smallest possible value of aaa.
Practise Edexcel A Level Maths Sequences and Series with exam-style questions for A Level Maths. 100 questions 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, 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.