炎德英才雅礼试卷五2022答案

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20.命题意图本题考查等差数列与等比数列的通项公式及分组求和法解析（I)设an}的公差为d(d≠0)，由a1,a4,a3成等比数列可知a=a,a13,即(a1 3d)2=a1·(a1 12d),化简得2a1=3d.(2分)由S5=35可得5a3=35,所以a1 2d=7.将2a1=3d代入，得a1=3,d=2,…(4分)所以an=3 (n-1)×2=2n 1.(6分)2n 3(Ⅱ)由(I)得bn=2m na=221 n2n 1’(8分)an所以Ta=b1 b2 b3 … bm=(2 2 * 2 h音 号 h》(10分)_8×(1-4) ln2m, 31-43一4=8×(4"- ln212n 33(12分)3

第二节参考范文:Soon, Mr Lim's business became better and better with the help of his eldest son. He often helped his fatherwith his work. This boy was very good with his hands. He proved very popular with his customers. It was hewho expanded his father's business after he dropped out of school when his father needed his help in their growing bicycle business. He started a motorcycle repairing service to add on to his fathers trade. Business at MrLims shop took off like a rocket and they soon lived a good life.It was at that time that my father 's business took a turn for the worse. One day, his senior assistant ranaway with a large amount of the shop's earnings, which led to my fathers being in debt. My father then sold ourfamily car to pay off the increasing bills. They say that one good deed deserves another. Mr Lim, came to learn ofour situation and stepped in to help. He stated simply that it was his turn to repay the kindness that my fatherhad shown to him in the past. With his generous help, my fathers business gradually return to normal