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1.7 D: Sequences and series

1.7 D: Sequences and series

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Question 147
a.

Show that

∑r=112(3r+7+2r)=8508\sum_{r=1}^{12} \left(3r + 7 + 2^r\right) = 8508∑r=112​(3r+7+2r)=8508

[4]
b.

A sequence u1,u2,u3,… u_1, u_2, u_3, \dots\,u1​,u2​,u3​,… is defined by

u1=25\displaystyle u_1 = \frac{2}{5}u1​=52​, un+1=1un\displaystyle u_{n+1} = \frac{1}{u_n}un+1​=un​1​

Find the exact value of ∑r=1100ur\sum_{r=1}^{100} u_r∑r=1100​ur​.

[3]
Markscheme

1.7 D: Sequences and series Questions

  1. A Level
  2. /Maths
  3. /1.7 D: Sequences and series

308 exam-style questions on AQA A Level Maths 1.7 D: Sequences and series, covering 1.7.1 Binomial expansion, 1.7.2 Types of sequence (A-level only), 1.7.3 Sigma notation (A-level only), 1.7.4 Arithmetic sequences and series (A-level only), 1.7.5 Geometric sequences and series (A-level only), and 1.7.6 Sequences and series in modelling (A-level only). Each one has a worked solution and a mark scheme showing where the marks go.

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