3.5 Sum to Infinity
18
0/8
i.

The power output of a prototype micro-sensor, PnP_nPn​ (in microwatts), during its nnn-th hour of operation is modeled by the geometric sequence Pn=45(0.8)nP_n = 45(0.8)^nPn​=45(0.8)n for n∈Nn \in \mathbb{N}n∈N. Calculate the total energy ∑n=1∞Pn\sum_{n=1}^{\infty} P_n∑n=1∞​Pn​ consumed by the sensor if it operates indefinitely.

[2]
a.

A sequence of experimental index values v1,v2,v3,… v_1, v_2, v_3, \dots\,v1​,v2​,v3​,… is defined by the recurrence relation: vn+1=11−vn,n∈Nv_{n+1} = \frac{1}{1 - v_n}, \quad n \in \mathbb{N}vn+1​=1−vn​1​,n∈N Given that the initial value is v1=23\displaystyle v_1 = \frac{2}{3}v1​=32​:

Show that this sequence is periodic.

[2]
b.

State the order of this sequence.

[1]
c.

Determine the sum of the first 100 terms of the sequence, ∑n=1100vn\sum_{n=1}^{100} v_n∑n=1100​vn​.

[3]

3.5 Sum to Infinity Questions

Practise Edexcel A Level Maths 3.5 Sum to Infinity with exam-style questions for A Level Maths. 18 questions, matched to the Edexcel A Level Maths (9MA0) specification and written in Paper 1, Paper 2 and Paper 3 style. Every question includes a full worked solution and mark scheme, so you can see where marks are awarded rather than just whether you got the answer right.

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3.5 Sum to Infinity Questions

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