Form 1 Maths

知識就是力量

2009-02-15 4:33 am

1. It is given that the nth term of a sequence is n^2 + 3. Is the difference between any two consecutive terms of the sequence a constant? Explain your answer.
2. Which of the follwing rulers would you choose to measure the thickness of Mathematics textbook? Explain your answer.
Ruler A - 5 cm with 0.1cm per unit
Ruler B - 5 cm with 1cm per unit

回答 (1)

Edward

2009-02-15 11:37 am

✔ 最佳答案

1. The the difference between any two consecutive terms of the sequence IS NOT a constant.
For 2nd term and 1st term, the difference = 2^2+3-1^2-3 = 7-4=3
For 3rd term and 2rd term, the difference = 3^2+3-2^2-3 = 12-7=5
From this 2 examples, the statement is persuasive enough to be disproved.

2. The absolute deviation of Ruler A = 0.1/2 = 0.05 cm
The absolute deviation of Ruler B = 1/2 = 0.5 cm

Since absolute deviation of Ruler B>absolute deviation of Ruler A,
ruler A is chosen.

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