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3.4 Sequences and Series (A-level only)

3.4 Sequences and Series (A-level only)

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Question 139
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

3.4 Sequences and Series (A-level only) Questions

  1. A Level
  2. /Maths
  3. /3.4 Sequences and Series (A-level only)

231 exam-style questions on WJEC A Level Maths 3.4 Sequences and Series (A-level only), covering 3.4.1 Sequences and Series (A-level only), 3.4.2 Sequences and Series (A-level only), 3.4.3 Sequences and Series (A-level only), 3.4.4 Sequences and Series (A-level only), 3.4.5 Sequences and Series (A-level only), 3.4.6 Sequences and Series (A-level only), and 3.4.7 Sequences and Series (A-level only). Each one has a worked solution and a mark scheme showing where the marks go.

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