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三峡名校联盟2022年秋季高2025届数学参考答案及评分细则一、单项选择题12345678BDBCCBBA二、多项选择题9101112ACADABDABC12.ABC解:由2336xy==可得:2log36x=,3log36y=,对于A:36
3636111log3log2log62xyxyyx+=+=+==,所以()2xyxy=+,故选项A正确;对于B:2222log36log4log92log9x==+=+,222log8log9log16
,即23log94,所以()22log95,6x=+,3333log36log9log42log4y==+=+,333loglog349log即31log42,所以()32log43,4y=+,所以8xy+,()216xyxy=+,故选项B
正确;对于C:22log3622log3x==+,33log3622log2y==+,所以()2322142log3log242log3log3xy+=++=++,令()2log31,2t=,则142xytt+=++在()1,2t上单调递
增,所以114242292xytt+=++++=,故选项C正确;对于D:()22log95,6x=+,()32log43,4y=+,所以22525x=,2239y=,所以2234xy+,故选项D不正确,故选:ABC.三、填空题13:xe(答案不唯
一例:)1(aax)14:1315:1620−;41516:33四、解答题17.解:(1)==22T.....2分(2)令.,2242Zkkx+=+则.,8Zkkx+=.....4分当.,8Zkkx+=函数有)(xf最大值21......6分(3)令=Z42+x。
Zysin21=在Zkkk++−],2222[,上单调递增。kxk224222+++−,kxk++−883.......8分−22,x.0时当=k883−x.]8,83[)(−的单增区间:函数xf.....1
0分18.解:(1)由题意,52)1(2222=+−=+=yxr,55252sin===ry.....2分212tan−=−==xy,.....4分554)2(552tansin−=−=......6分分)(8..........5551cos2−=−==r
x)sin().tan()2sin()23cos()2tan()27cos()2sin()(+−−−+−−−+=f)sin).(tan((sin)sin()tan()sin(cos−−−−−−=cos=
55−=......12分注:第一问6分,第二问6分.第二问化简4分,6个三角函数值错一个扣1分,直到扣完。如果第一问求了55cos−=第二问可以不求.19.解:选①,()21log2+x,()4log1log22+x,410+x,31−x.31−=xxB.选②
16211+x,410222+x,410+x,31−x.31−=xxB.......3分(1)当0=a时,11−=xxA,=ACR1,1−xxx或,BACR)(31=xx.......6分(2)“xA”是“x
B”的充分不必要条件,①=A,.121+−aa2−a.......8分②,A2−a+−−31211aa或+−−31211aa.10a.综上所述:2−a或10a..
.....12分注:第二问没取等号扣1分,20.解:)3(log)(2++=axxxfa,)10(aa且。(1)当,4=a)34(log)(24++=xxxf,令,0342++xx,0)3)(1(++xx.1,3−−xx或)34(log)(24++=xxxf定义域:),(3−−
),(+−1令342++=xxt,ty4log=.342++=xxt在),(3−−单减,在),(+−1单增。ty4log=在),(+0单增.......2分)34(log)(24++=xxxf单增区间:),(+−1.......3分)34(log)(24++=xxxf单减区间:)
,(3−−.......4分(2)若函数,的定义域为Rxfy)(=恒成立,则032++axx0122−a,3232−a,......7分又10aa且.321,10aa或.......8分(3)函数),,的值域为+=1)(xfytyalog=令,32++=a
xxt4343)2(32222aaaxaxxt−−++=++=结合tyalog=单调性和图像。1a...10分此时32++=axxt值域),,+aaa=−43201242=−+aa,,0)2)(6(=−+aa2,1=aa
.......12分21.解:(1)由题意可得()()250230,0210()203048048030,251xxxfxWxxxxxx+−=−−=−−+,即()25030100,021648030,251xxxfxxxx−
+=−++,所以函数()fx的函数关系式为()25030100,021648030,251xxxfxxxx−+=−++.......5分(2)当02x时,()25030100fxxx=−+为开口向上的抛物线,对称轴为3032
5010x−=−=,所以当2x=时()()2max2502302100240fxf==−+=,......7分当25x时,()1616164803048030130510301111fxxxxxxx
=−+=−+++=−+++++()1651030212701xx−+=+,......10分当且仅当1611xx=++即3x=时等号成立,此时()min270fx=,......11分综上所述:当投入的肥料费
用为31030=元时,单株水果树获得的利润最大为270元.......12分.22.解:(1)令.0==yx0)0(),0()0()00(=+=+ffff.令,xy−=),()()(xfxfxxf−+=−,0)()(=−+xfxf)(xf是奇函数.......
2分(2)令,21,xxxyx==+则21xxy−=.不妨设,21xx),()()(yfxfyxf+=+),()()(2121xxfxfxf−+=)()()(2121xxfxfxf−=−,0x时,有.0)(
xf0)()(21−xfxf,.)(上单调递增在Rxf......4分令21−==yx,则2)21(2)1(−=−=−ff,令1−==yx,则4)1(2)2(−=−=−ff,4)2(=f.)2(4)()552525(,0222++=+++++kkfkkftttft都
有,.)(上单调递增在Rxf2552525,022+++++kktttt都有,......5分设,]311)1[(251)1(251)1(3)1(252555)(22++++=+++++=+++=tttttttttu)1(1
+=wtw令,.11)单调递增,在(++ww,21+ww51]311)1[(251)(++++=tttu.......6分,252++kk,032−+kk,0)2131)(2131(−−−+−−kk或,2131+−k.2131−−k......7分(3)
23)1(=f,令1==yx,则3)1(2)2(==ff,3)2(=f.3)2(−=−f.03]2)()3())([(2=−−+−mxgmxgf)0(]22)()3())([(2fmxgmxgf=−−+−.)(上单调递增在Rxf022)()3())((2=−−
+−mxgmxg......8分有三个不同的零点,,令txg=)(022)3(2=−−+−mtmt.12−=xt.21012,,交点个数为与−==xyty.210022)3(2,,的解的个数为=−−+−mtmt。必有两个不同解2
12,022)3(ttmtmt=−−+−且),(101t,.1,02=tttt或①舍去)方程,(,2,02,10122==−−==tttmt,......9分②.32,0323534,022311122成立方程,==+−−==−−−−=tttmmmt......10分③−
−+−−−+−02213(10220)3(022mmmm).134−−m综上所述:.134−−m......12分获得更多资源请扫码加入享学资源网微信公众号www.xiangxue100.com