参考答案1.答案:A解析:因为|37Axxx或,所以|37UAxxð.又()UABð,所以3a.故选A.2.答案:D解析:若命题:{|12}pxxx,20xa为真命题,则2ax在{|12}xxx时恒成立,1a.若命题:qxR,2240xax为真命题,则2(2)160a,解得2a或2a.命题p和命题q都是真命题,1,2 2,aaa或解得2a.故选D.3.答案:A解析:由2()00abaa且ab,∴充分性成立;由0abab,当0ab时,2()0aba,必要性不成立,故选A.4.答案:D解析:由题意,4fxm,可得215mxx.∵当[1,3]x时,211,7xx,∴不等式 0fx等价于251mxx.∵当3x时,251xx的最小值为57,∴若要不等式251mxx恒成立,则必须57m,因此,实数 m的取值范围为5,7,故选:D.5.答案:B6.答案:C解析:2,022,0xxxxyx,画出图像即可.7.答案:A8.答案:D9.答案:B10.答案:B解析:()fx为偶函数,()()(||)fxfxfx,1(21)2fxf等价于1(|21|)2fxf,又函数()fx在区间[0,)上单调递增,1|21|2x,即112122x,1344x.故选B.11.答案:A解析:由函数()fx是偶函数知,(3)(3)ff,(2)(2)ff,又[0,)x时()fx是增函数,(π)(3)(2)fff,(π)(3)(2)fff,故选A.12.答案:C解析:令()e1xfx,得0x,由()|ln|0fxx,得11x,令()|ln|1fxx,得ex,或1e,由()eexfx,得21x(舍去正值);由()|ln|efxx,得e3ex,或e4ex;由1()eexfx,得51x;由1()|ln|efxx,得1e6ex,或1e7ex.所以函数(())1yffx的零点个数为6,故选C.13.答案:81解析:幂函数fxx的图像过点2,2,∴22=2f,解得2,∴2fxx,2(9)981f故答案为81.14.答案:4022解析:令1b,则有11fafaf,∴112faffa,∴2320122,2,...,2,122011ffffff∴2320122,2,...,201124022122011ffffff.15.答案:4∵23692lg3lglg6lg11log3loglog6loglg2lg36lg94lg242mmmm,∴2log2m,∴4m.16.答案:2sxsx17.答案:证明:由0,0ab,且232ab,可得262ab,即16ab,当且仅当23232abab,即1213ab,时,取等号.········5分设tab,则106t,易得函数1ytt在1(0,]6上单调递减,∴11666abab,即16abab.·············10分18.答案:(1)根据题意,设该公司的总收入为W万元,则501018100xxW,0100x.·········3分若该公司月总收入不减少,则有5010110508100xx,解得020x.······················6分(2)设该公司总盈利为y万元,则2501012104808100816xxxxyx,0100x,结合二次函数的性质分析可得,当8x时,该公司的总盈利最大.······12分19.答案:(1)由已知得122a,解得1a.········3分(2)由(1)知12xfx.因为gxfx,所以1422xx,即112042xx,即2112022xx.··············7分令12xt,即220tt,即210tt.又因为0t,所以2t,即122x,解得1x.···········12分20.答案:由已知得,1142xxa,·········2分∵函数14xy和12xy在R上都是减函数,···········4分∴当,1x时,1111,4422xx,∴1111342424xx,从而113424xx,故实数a的取值范围为3,4.·············12分21.答案:(1)由()()fxfx得222244xxaxxxax,即20ax对任意实数x都成立,0a.·········3分(2)当[2,2]x时,()44fxx,令440x,解得1x;·······5分当2x或2x时,2()244fxxx,令22440xx,解得13x,13x.············7分综上,函数()fx的零点为-1和13.···········8分(3)当||2x时,()4fxax,令40ax,可知方程在(0,4)上最多有一个实数根;当||2x时,2()24fxxax,令2240xax,若1x,2x均为该方程在(0,4)上的根,则122xx,不符合题意.故1(0,2]x,2(2,4)x.由140ax得14ax,2a;由222240xax得2242axx,72a.综上所述,a的取值范围为72a.·········12分22.答案:(1)由函数2234fxxmxm有且仅有一个零点,知方程0fx有两个相等的实数根,所以0,即244340mm,········3分即2340mm,解得4m或1m.·········5分(2)由题意,知244(34)01(1)0mmmf,即2340112340mmmmm,······10分解得51m,所以实数m的取值范围为(5,1).·········12分
,