2008年普通高等学校招生全国统一考试 理科数学试题(必修?选修Ⅱ)参考答案和评分参考
评分说明:
1.本解答给出了一种或几种解法供参考,如果考生的解法与本解答不同,可根据试题的主要 考查内容比照评分参考制订相应的评分细则.
2.对计算题,当考生的解答在某一步出现错误时,如果后继部分的解答未改变该题的内容和 难度,可视影响的程度决定后继部分的给分,但不得超过该部分正确解答应得分数的一半;如果后继部分的解答有较严重的错误,就不再给分.
3.解答右端所注分数,表示考生正确做到这一步应得的累加分数. 4.只给整数分数.选择题不给中间分.
一、选择题
1.B 2.A 3.C 4.C 5.D 6.D 7.B 8.B 9.B 10.C 11.A 12.C 二、填空题
13.2 14.2 5.3?22 16.两组相对侧面分别平行;一组相对侧面平行且全等;对角线交于一点;底面是平行四边形.
注:上面给出了四个充要条件.如果考生写出其他正确答案,同样给分. 三、解答题 17.解:
512,得sinB?, 131343由cosC?,得sinC?.
55(Ⅰ)由cosB??所以sinA?sin(B?C)?sinBcosC?cosBsinC?(Ⅱ)由S△ABC?33. ··············································· 5分 6533得 2133, ?AB?AC?sinA?2233由(Ⅰ)知sinA?,
65故 AB?AC?65, ··································································································· 8分
AB?sinB20又 AC??AB,
sinC132013故 AB2?65,AB?.
132
所以 BC?
18.解:
AB?sinA11·················································································· 10分 ?. ·
sinC2各投保人是否出险互相独立,且出险的概率都是p,记投保的10 000人中出险的人数为?, 则?~B(10,p).
(Ⅰ)记A表示事件:保险公司为该险种至少支付10 000元赔偿金,则A发生当且仅当??0, ······························································································································· 2分
4P(A)?1?P(A)
?1?P(??0) ?1?(1?p)10,
10又P(A)?1?0.999,
44故p?0.001. ························································································································ 5分 (Ⅱ)该险种总收入为10000a元,支出是赔偿金总额与成本的和. 支出 10000??50000,
盈利 ??10000a?(10000??50000), 盈利的期望为 E??1000a0?4?3100E?0?0?3······················································ 9分 5,0 010)知,E??10000?10, 由?~B(10,E??104a?104E??5?104
?104a?104?104?10?3?5?104. E?≥0?104a?104?10?5?104≥0
?a?10?5≥0 ?a≥15(元).
故每位投保人应交纳的最低保费为15元.········································································· 12分
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