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第I卷(选择题共60分)一、选择题(每小题5分,共60分)请将下列各题唯一正确结论的代号填写在答题卡内 1.巳知角α的终边经过点A(5α,-12α),其中α<0,则sinα的值为( ) (A)-12/13. (B)12/13.(C)5/13. (D)-5/13.2.{a_n}为等差数列,S_n为其前n项和,S5S8,则下列错误的是( )(A)d<0.(B)a7=0.(C)S9>S5.(D)S6和S7均为S_n的最大值.
Volume I (Multiple Choice Questions with 60 Points) I. Multiple-choice questions (5 points for each question, 60 points in total) Please fill out the following code for the only correct conclusion in the answer sheet. 1. Pass through the end of the knowledge angle α. Point A (5α,-12α), where α<0, then the value of sinα is () (A)-12/13. (B)12/13. (C)5/13. (D)-5/13.2 .{a_n} is the arithmetic progression, S_n is the sum of the preceding n entries, S5S8, then the following error is ()(A)d<0.(B)a7=0.(C S9>S5. (D) S6 and S7 are the maximum values of S_n.