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.
308 exam-style questions on OCR A Level Maths 1.4 Sequences and Series, covering 1.4.1 Binomial expansion for positive integer n, 1.4.2 Link to binomial probabilities, 1.4.3 Binomial expansion for rational n (A-level only), 1.4.4 Validity of the expansion (A-level only), 1.4.5 Sequences (A-level only), 1.4.6 Increasing, decreasing and periodic sequences (A-level only), 1.4.7 Sigma notation (A-level only), 1.4.8 Arithmetic sequences and series (A-level only), 1.4.9 Geometric sequences and series (A-level only), 1.4.10 Sum to infinity of a geometric series (A-level only), and 1.4.11 Modelling with sequences and series (A-level only). Each one has a worked solution and a mark scheme showing where the marks go.