OCR A-level Mathematics A · H240

Sigma notation

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Extreme practice · Multi-step problems within A-level pure maths. Difficulty is an editorial judgement. These questions are self-reviewed, not ranked.

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Calculator permitted. Give clear working in the answer booklet and label each part. Formulae are provided in the official question paper.

Original topic practice. This set is not a full official paper. Written work is self-reviewed against our worked solutions.

01 · Pure · 100 marks · 2 hours
02 · Pure & statistics · 100 marks · 2 hours
03 · Pure & mechanics · 100 marks · 2 hours

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QUESTION PAPER

Mathematics · A levelPure mathematics · H240/01

Torus Maths original · OCR style

A sequence is defined by $u_n=(n+3)/2^n$ , $n\geq1$ . Let $S_N=u_1+\cdots+u_N$ .

(a)

Find a simplified expression for S_N in terms of N.

[5]

(b)

Find the sum to infinity. Find the least N for which the difference between S_N and this sum is at most 0.01.

[4]

Question reference: ocr-a-level-extreme-11-01Report a question →

Answer booklet

Question 1 · Show your working

(a)

Answer booklet · Question 1(a)

(b)

Answer booklet · Question 1(b)

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