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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 135

The total energy E(n)E(n)E(n) released by a sequence of n n\,n laser pulses in a laboratory experiment is given by the sum E(n)=∑j=0n(2j)4E(n) = \sum_{j=0}^{n} (2j)^4E(n)=∑j=0n​(2j)4 millijoules, where n n\,n is a positive integer. The specific energy produced by the nnn-th pulse is defined as P(n)=E(n)−E(n−1)P(n) = E(n) - E(n-1)P(n)=E(n)−E(n−1).

a.

Determine the specific energy released by the 3rd pulse, P(3)P(3)P(3), and the 10th pulse, P(10)P(10)P(10).

[2]
b.

Find the pulse number n n\,n such that the specific energy released is P(n)=8.1×109P(n) = 8.1 \times 10^9P(n)=8.1×109 millijoules.

[4]
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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