The first four terms of a sequence are 2 \times 3, 5 \times 5, 8 \times 7, 11 \times 9.
If S_n denotes the series formed by summing the first n terms of the sequence, find S_n in terms of n.
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Practise this questionr, the r^{\text{th}} term of the sequence.[2 marks]9^{\text{th}} term of an A.P. is three times the 3^{\text{rd}} term and the sum of the first 10 terms is 110. Find the first term a and the common…[6 marks](1 + 2x)^{\frac{1}{2}} as far as the term in x^3, stating the values of x for which the expansion is valid.[5 marks]\frac{x}{1 + x + \sqrt{1 + 2x}} = \frac{1}{x}(1 + x - \sqrt{1 + 2x}) for x > 0.[4 marks]x is small so that the term in x^3 and higher powers of x can be neglected, the expansion in (c)(ii) above is…[3 marks]More practice: the rest of this paper · more Series questions · all CAPE Pure Mathematics Unit 2 past papers