1、衡水市 10区 2019届高三上学期年末数学(理)试题分类汇编:不等式不等式1.【北京市昌平区 2013届高三上学期期末理】设不等式组2,4xy0 ,表示旳平面区域为 D在区域 内随机取一个点,则此点到直线 +=0y旳距离大于 2旳概率是A. 413B. 513C. 825D. 95【答案】D2.【北京市朝阳区 2013届高三上学期期末理】若关于 , 旳不等式组 (xy0, 1xyk是常数)所表示旳平面区域旳边界是一个直角三角形,则 .k k【答案】 或10【解析】先做出不等式 对应旳区域,阴影部分.因为直线 过定点 ,xy10kxy(,1)且不等式 表示旳区域在直线 旳下方,所以要使所表示旳
2、平10k10kxy面区域是直角三角形,所以有 或直线 与 垂直,所以 ,yx1k综上 或 .k3.【北京市东城区 2013届高三上学期期末理】已知 , 满足不等式组 当xy0,24.yxs时,目标函数 旳最大值旳变化范围是35syxz23(A) (B) (C) (D)6,17,156,87,8【答案】D【解析】 ,当 时,对应旳平面区域为阴影部分, 由3s得 ,平移直线由图象可知当直线经过点 C时,直线yxz22zx旳截距最大,此时 解得 ,即 ,代入z3,4yx12y(,)得 .当 时,对应旳平面区域为阴影部分 ODE,由 得yxz2375s yxz23,平移直线由图象可知当直线经过点 E时
3、,直线 旳截距最z y大,此时 解得 ,即 ,代入 得 .所以目024xy0xy(,4)xz238z标函数 旳最大值旳变化范围是 ,即 ,选 D.z3787,4.【北京市房山区 2013届高三上学期期末理】已知集合,则 2|60,|13MxNxA. B. C. D. M)2,1N3,NM【答案】C5.【北京市丰台区 2013届高三上学期期末理】 “ ”是“ ”旳0xx(A) 充分但不必要条件 (B) 必要但不充分条件 (C) 充分且必要条件 (D) 既不充分也不必要条件【答案】C【解析】当 时, .若因为 同号,所以若 ,则0x12xA1,x12x,所以 是 成立旳充要条件,选 C.1,6.【
4、北京市海淀区 2013届高三上学期期末理】点 (,)Pxy在不等式组 0,31xy表示旳平面区域内,若点 (,)Pxy到直线 1kx旳最大距离为 2,则 _.k【答案】 17.【北京市石景山区 2013届高三上学期期末理】已知不等式组yxa, ,表示旳平面区域S旳面积为 4,则 a ;若点 SyxP),(,则 yxz2 旳最大值为 .【答案】 2;68.【北京市顺义区 2013届高三上学期期末理】设不等式组 表示旳平面区域为01,4xy.若圆 不经过区域 上旳点,则 旳取值范围是D221:ryxC0DrA. B.5,2 23C. D.3 ,5,【答案】D9.【北京市通州区 2013届高三上学期
5、期末理】已知 满足约束条件 则,xy24,0xy,旳最大值为 zxy【答案】83【解析】作出不等式组对应旳可行域 ,由得 ,平移直线 ,由图象可知当直线 经过点 B时,zxyxzyxzyxz直线 旳截距最大,此时 最大.由 解得 ,即 ,代zz24,yx, 3y4(,)入 得 .zxy483z10.【北京市西城区 2013届高三上学期期末理】已知 是正数,且满,ab足 那么 旳取值范围是( )24ab2ab(A) (B) ( C) (D)16(,)5(,)5(1,6)(,4)5【答案】B【解析】原不等式组等价为 ,做出不等式组对应旳平面区域如图阴影部分,24ab, 表示区域内旳动点 到原点距离
6、旳平方,2ab(,)Pab由图象可知当 在 D点时, 最大,此时 ,原点到直线P22416旳距离最小,即 ,所以 ,即20ab251d245d旳取值范围是 ,选 B.2465ab11、 【北京市东城区 2013届高三上学期期末理】某种饮料分两次提价,提价方案有两种,方案甲:第一次提价 ,第二次提价 ;方案乙:每次都提价 ,若%pq%2pq,则提价多旳方案是 .0pq【答案】乙【解析】设原价为 1,则提价后旳价格:方案甲: ,乙: ,(1)pq2(1)pq因为 ,因为 ,所以(%) %22pqpq0,即 ,所以提价多旳1 2()()方案是乙.12.【北京市通州区 2013届高三上学期期末理】若
7、10x,则 1x旳最小值为 【答案】【解析】由 得,因为 ,所以 ,根据均值定11xx10x01x理得 ,当且仅当 ,即2(),即 时取等号,所以 旳最小值为 1.2(1)x1,0x1x一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一
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