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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 133

The electrical current InI_nIn​, measured in milliamperes, flowing through a logic gate is monitored at discrete clock cycles. The sequence of current values is defined by the recurrence relation

I1=0.4andIn+1=12Infor n≥1 I_1 = 0.4 \quad \text{and} \quad I_{n+1} = \frac{1}{2I_n} \quad \text{for } n \ge 1 I1​=0.4andIn+1​=2In​1​for n≥1
a.

Find the values of I2I_2I2​, I3I_3I3​ and I4I_4I4​.

[3]
b.

State the period of the sequence.

[1]
c.

Determine the exact value of ∑n=1101In\sum_{n=1}^{101} I_n∑n=1101​In​.

[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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