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笔者有幸参加了2014年浙江高考数学理科卷的阅卷工作,觉得收获颇丰.现将阅卷反馈呈现如下,并就此做一些思考,供大家在教学中参考.第19题:已知数列{a_n}和{b_n}满足a_1a_2a_3…a_n=(2~(1/2))~(b_n)(n∈N~*).若{a_n}为等比数列,且a_1=2,b_3=6+b_2.(1)求a_n与b_n;(2)设c_n=1/a_n-1/b_n(n∈N~*).记数列{c_n}的前n项和为S_n.(i)求S_n;(ii)求正整数k,使得对任意k∈N~*均有S_k≥S_n.1.阅卷反馈1.1评分标准的制定评分标准,命题组只给出了两小题各7分的大原
The author was fortunate to participate in the examination of the 2014 Zhejiang Mathematics for Mathematics for Mathematics of the College Entrance Examination. He felt that the harvest was quite good. The feedback on the reading was presented as follows and some thoughts were made for reference in the teaching. Question 19: Known sequence {a_n} And {b_n} satisfies a_1a_2a_3...a_n=(2~(1/2))~(b_n)(n∈N~*). If {a_n} is a geometric sequence, and a_1=2, b_3=6+b_2. (1) find a_n and b_n; (2) set c_n=1/a_n-1/b_n(n∈N~*). Count the first n items in the list {c_n} and S_n.(i) find S_n; ( Ii) Determine the positive integer k so that for any k∈N~*, S_k ≥S_n.1. Marking criteria for marking the 1.1 rating of scoring feedback, and the proposition group only gives a score of 7 points for each of the two points.