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,回扣,1,集合与惯用逻辑用语,考前回扣,1/34,基础回归,易错提醒,回归训练,2/34,基础回归,3/34,1.,集合,(1),集合运算性质:,A,B,A,B,A,;,A,B,B,B,A,;,A,B,U,A,U,B,.,(2),子集、真子集个数计算公式,对于含有,n,个元素有限集合,M,,其子集、真子集、非空子集、非空真子集个数依次为,2,n,2,n,1,2,n,1,2,n,2.,(3),集合运算中惯用方法,若已知集合是不等式解集,用数轴求解;若已知集合是点集,用数形结正当求解;若已知集合是抽象集合,用,Venn,图求解,.,4/34,2.,四种命题及其相互关系,(1),(2),互为逆否命题两命题同真同假,.,5/34,3.,含有逻辑联结词命题真假,(1),命题,p,q,:若,p,,,q,中最少有一个为真,则命题为真命题,简记为:一真则真,.,(2),命题,p,q,:若,p,,,q,中最少有一个为假,则命题为假命题,,p,,,q,同为真时,命题才为真命题,简记为:一假则假,同真则真,.,(3),命题,綈,p,:与命题,p,真假相反,.,6/34,4.,全称命题、特称,(,存在性,),命题及其否定,(1),全称命题,p,:,x,M,,,p,(,x,),,其否定为特称,(,存在性,),命题,綈,p,:,x,0,M,,,綈,p,(,x,0,).,(2),特称,(,存在性,),命题,p,:,x,0,M,,,p,(,x,0,),,其否定为全称命题,綈,p,:,x,M,,,綈,p,(,x,).,7/34,5.,充分条件与必要条件三种判定方法,(1),定义法:正、反方向推理,若,p,q,,则,p,是,q,充分条件,(,或,q,是,p,必要条件,),;若,p,q,,且,q,p,,则,p,是,q,充分无须要条件,(,或,q,是,p,必要不充分条件,).,(2),集正当:利用集合间包含关系,.,比如,若,A,B,,则,A,是,B,充分条件,(,B,是,A,必要条件,),;若,A,B,,则,A,是,B,充要条件,.,(3),等价法:将命题等价转化为另一个便于判断真假命题,.,8/34,易错提醒,9/34,1.,描述法表示集合时,一定要了解好集合含义,抓住集合代表元素,.,如,x,|,y,lg,x,函数定义域;,y,|,y,lg,x,函数值域;,(,x,,,y,)|,y,lg,x,函数图象上点集,.,2.,易混同,0,,,,,0,:,0,是一个实数;,是一个集合,它含有,0,个元素;,0,是以,0,为元素单元素集合,不过,0,,而,0.,3.,集合元素含有确定性、无序性和互异性,在处理相关集合问题时,尤其要注意元素互异性,.,4.,空集是任何集合子集,.,由条件,A,B,,,A,B,A,,,A,B,B,求解集合,A,时,务必分析研究,A,情况,.,10/34,5.,区分命题否定是否命题,已知命题为,“,若,p,,则,q,”,,则该命题否定为,“,若,p,,则,綈,q,”,,其否命题为,“,若,綈,p,,则,綈,q,”.,6.,在对全称命题和特称,(,存在性,),命题进行否定时,不要忽略对量词改变,.,7.,对于充分、必要条件问题,首先要搞清谁是条件,谁是结论,.,8.,判断命题真假要先明确命题组成,.,由命题真假求某个参数取值范围,还能够从集合角度来思索,将问题转化为集合间运算,.,11/34,III,回归训练,12/34,答案,解析,1.,设集合,M,x,Z,|,3,x,2,,,N,x,Z,|,1,x,3,,则,M,N,等于,A.0,1 B.,1,0,1,2,C.0,1,2 D.,1,0,1,解析,M,x,Z,|,3,x,2,2,,,1,0,1,,,N,x,Z,|,1,x,3,1,0,1,2,3,,,M,N,1,0,1,,故选,D.,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,13/34,答案,解析,2.,已知集合,A,x,|,x,2,4,x,3,0,,,B,y,|,y,2,x,1,,,x,0,,则,A,B,等于,A.,B.0,1),(3,,,),C.,A,D.,B,解析,由题意,得集合,A,x,|1,x,3,,集合,B,y,|,y,0,,那么,A,B,x,|1,x,3,A,.,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,14/34,答案,解析,3.,已知集合,M,x,|log,2,x,3,,,N,x,|,x,2,n,1,,,n,N,,则,M,N,等于,A.(0,8)B.3,5,7,C.0,1,3,5,7 D.1,3,5,7,解析,M,x,|0,x,8,,又,N,x,|,x,2,n,1,,,n,N,,,M,N,1,3,5,7,,故选,D.,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,15/34,答案,解析,4.,已知集合,A,1,2,3,4,5,,,B,5,6,7,,,C,(,x,,,y,)|,x,A,,,y,A,,,x,y,B,,则,C,中所含元素个数为,A.5 B.6C.12 D.13,解析,若,x,5,A,,,y,1,A,,则,x,y,5,1,6,B,,即点,(5,1),C,;,同理,,(5,2),C,,,(4,1),C,,,(4,2),C,,,(4,3),C,,,(3,2),C,,,(3,3),C,,,(3,4),C,,,(2,3),C,,,(2,4),C,,,(2,5),C,,,(1,4),C,,,(1,5),C,,,所以,C,中所含元素个数为,13,,故选,D.,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,16/34,答案,解析,5.,已知集合,A,y,|,y,sin,x,,,x,R,,集合,B,x,|,y,lg,x,,则,(,R,A,),B,为,A.(,,,1),(1,,,)B.,1,1,C.(1,,,)D.1,,,),解析,因为,A,y,|,y,sin,x,,,x,R,1,1,,,B,x,|,y,lg,x,(0,,,),,,所以,(,R,A,),B,(1,,,).,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17/34,答案,解析,6.,设有两个命题,命题,p,:关于,x,不等式,(,x,3),0,解集为,x,|,x,3,,命题,q,:若函数,y,kx,2,kx,8,值恒小于,0,,则,32,k,0,,那么,A.,“,p,且,q,”,为真命题,B.,“,p,或,q,”,为真命题,C.,“,綈,p,”,为真命题,D.,“,綈,q,”,为假命题,解析,不等式,(,x,3),0,解集为,x,|,x,3,或,x,1,,所以命题,p,为假命题,.,若函数,y,kx,2,kx,8,值恒小于,0,,则,32,k,0,,,所以命题,q,也是假命题,所以,“,綈,p,”,为真命题,.,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,18/34,答案,解析,7.(,天津,),设,a,n,是首项为正数等比数列,公比为,q,,则,“,q,0,”,是,“,对任意正整数,n,,,a,2,n,1,a,2,n,0,”,A.,充要条件,B.,充分无须要条件,C.,必要不充分条件,D.,既不充分也无须要条件,解析,设数列首项为,a,1,,则,a,2,n,1,a,2,n,a,1,q,2,n,2,a,1,q,2,n,1,a,1,q,2,n,2,(1,q,)0,,即,q,1,,,故,q,0,是,q,1,必要不充分条件,.,故选,C.,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,19/34,答案,解析,8.,设命题甲:,ax,2,2,ax,1,0,解集是实数集,R,;命题乙:,0,a,1,,则命题甲是命题乙成立,A.,充分无须要条件,B.,充要条件,C.,必要不充分条件,D.,既不充分也无须要条件,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,20/34,解析,由命题甲:,ax,2,2,ax,1,0,解集是实数集,R,可知,,当,a,0,时,原式,1,0,恒成立,,解得,0,a,1,,所以,0,a,1,,,所以由甲不能推出乙,而由乙可推出甲,,所以命题甲是命题乙成立必要不充分条件,故选,C.,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,21/34,答案,解析,9.,设命题,p,:函数,y,sin 2,x,最小正周期为,;命题,q,:函数,y,cos,x,图象关于直线,x,对称,.,则以下判断正确是,A.,p,为真,B.,綈,q,为假,C.,p,q,为假,D.,p,q,为真,解析,p,是假命题,,q,是假命题,所以只有,C,正确,.,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,22/34,答案,解析,10.,已知集合,M,x,|,3,x,5,,,N,x,|,x,5,,则,M,N,等于,A.,x,|,3,x,5 B.,x,|,5,x,5,C.,x,|,x,3 D.,x,|,x,5,解析,在数轴上表示集合,M,,,N,,则,M,N,x,|,x,3,,故选,C.,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,23/34,答案,解析,11.,以下四个结论:,若,x,0,,则,x,sin,x,恒成立;,命题,“,若,x,sin,x,0,,则,x,0,”,逆否命题为,“,若,x,0,,则,x,sin,x,0,”,;,“,命题,p,q,为真,”,是,“,命题,p,q,为真,”,充分无须要条件;,命题,“,x,R,,,x,ln,x,0,”,否定是,“,x,0,R,,,x,0,ln,x,0,0,时,,x,sin,x,0,0,0,,即当,x,0,时,,x,sin,x,恒成立,故,正确;,对于,,命题,“,若,x,sin,x,0,,则,x,0,”,逆否命题为,“,若,x,0,,则,x,sin,x,0,”,,故,正确;,对于,,命题,p,q,为真即,p,,,q,中最少有一个为真,,p,q,为真即,p,,,q,都为真,可知,“,p,q,为真,”,是,“,p,q,为真,”,充分无须要条件,故,正确;,对于,,命题,“,x,R,,,x,ln,x,0,”,否定是,“,x,0,R,,,x,0,ln,x,0,0,”,,故,错误,.,综上,正确结论个数为,3,,故选,C.,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,25/34,答案,解析,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,26/34,当集合,M,N,长度取最小值时,,M,与,N,应分别在区间,0,1,左右两端,.,取,m,最小值,0,,,n,最大值,1,,,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,27/34,故选,C.,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,28/34,答案,解析,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,29/34,得,(,ax,5)(,x,2,a,),0,,,当,a,0,时,显然不成立,,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,30/34,解得,9,a,25,,当,a,0,时,不符合条件,.,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,31/34,0,故,m,(tan,x,1),min,,,m,0,,故实数,m,最大值为,0.,答案,解析,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,32/34,答案,解析,1,函数,y,f,(,x,),图象不过第三象限,,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,33/34,答案,解析,16.,以下结论:,命题,“,若,x,1,,则,x,2,3,x,2,0,”,逆否命题是,“,若,x,2,3,x,2,0,,则,x,1,”,;,“,x,2,”,是,“,x,2,3,x,2,0,”,充分无须要条件;,若,“,命题,p,:,x,R,,,x,2,x,1,0,”,,则,“,綈,p,:,x,0,R,,,x,x,0,1,0,”,;,若,“,p,q,”,为真命题,则,p,,,q,均为真命题,.,其中错误结论序号是,_.,解析,对于若,“,p,q,”,为真命题,则,p,,,q,中最少有一个为真命题,所以,错误,.,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,34/34,
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