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遂宁市高中2024届零诊考试数学(理科)试题参考答案及评分意见一、选择题(每小题5分,12小题,共60分)题号123456789101112答案DACABBCADCBD二、填空题(每小题5分,4个小题,共20分)13.1014.515.216.
1012,1011三、解答题17.(1)()2π23sincos2sin3sin2cos212sin216fxxxxxxx=−=+=−+−,..............3分因为kxk222222+++−,所以
kxk++−63,..........................5分故函数)(xfy=在单调增区间为+−6,3kk)(Zk;....................
.............6分(2)将()fx向左平移m个单位得到1()2sin(2())16fxxm=++−将1()fx纵坐标不变,横坐标变为原来的两倍得到1)62sin(2)(−++=mxxg,又因为()
ygx=的图象关于直线3=x对称,则2623+=++km,...............9分解得:Zkkm=,2,.......................................
.......................................................10分因为0m,所以当1k=时,2=m取得最小值,.................................................11分故1)6sin(
2)(−+−=xxg............................................................................................12分18.(1)当2n时,331)1()1(221+−=+−−−=−nnnnSn
...................................1分22)33(1221−=+−−+−=−=−nnnnnSSannn......................................................
..3分当1=n时,111==Sa..................................................................................................................4分故1,1()22,2nnan
Nnn==−................................................................................................5分(2)212111211=
==aab..............................................................................................
.......................6分当2n时,)111(412)22(111nnnnaabnnn−−=−==+..........................................................8分故)1111121...3121211(4121
...21nnnnbbbTnn−−+−−−++−+−+=+++==nn4143)11(4121−=−+..................................................................................
.........................10分要使,6445nT即,64454143−n解得,316n又Nn,故n的最大值为5........12分19.(1)由正弦定理,sincossinabbABB
==,所以sincosBB=,4B=.....................1分11sin22ABCSahacB==△,则112313222c=,所以2c=...............
......3分又由余弦定理,2222cos5bacaB=+−=,所以5b=........................................5分所以22210cos210bcaAbc+−==−.........................................
.................................6分(2)由正弦定理,3sinsinsincaCAA==,所以33sin3sin3141sinsintan2ACcAAA−===+....
..............................................................8分又因为锐角ABC△,所以0,230,42AA−解得42A,所以101tanA
...........................................................................................................................9分所以36
22c,所以13299sin,2442ABCSacBc==△..............................11分即ABC△面积的取值范围是99,42....
...................................................................12分20.(1)若2=a,则)1)(13(143)(2'++=++=xxxxxf令0)('=xf,解得31,121−=−=xx.............
.....................................................2分当x变化时,)(),('xfxf的取值情况如下:x)1,(−−1−)31,1(−−31−),31(+−)('xf+0
−0+)(xf单调递增极大值单调递减极小值单调递增且02723)31(,01)1(,01)2(=−=−−=−fff.......................................................
4分根据零点存在定理可得:)(xf在)1,2(−−有一个零点,所以函数)(xf的极大值为1,极小值为2723,且)(xf有1个零点....................5分(2)由题意知,12,xx是方程23210xax++=的两个不等实根,且12xx,23a由韦达定理知,222
1212122142,,3393axxxxxxa+=−=+=−,222121212442()43933xxxxxxaa−=−+−=−−=−−.....................................................8分所以()(
)()()32321211122211fxfxxaxxxaxx−=+++−+++()()()22121122121xxxxxxaxx=−+++++..............................................
.......................9分()2322224124313393327aaaa=−−−−+=−..................................................................10分其中3a−或3a.令2
3ta=−,则30427(),gttt=,因为()gt在(0,)+单调递增...........................11分所以()()12fxfx−的取值范围是()0,+.........
..........................................................12分21.(1)∵xaexfx−=3)(,∴13)(3−=xaexf..................................
......................1分(i)当0a时,0)(xf,所以)(xf在R上单调递减............................................3分(ii
)当0a时,令0)(=xf,得33lnax−=所以)(xf在−−33ln,a上单调递减,在+−,33lna上单调递增..........5分(2)由题意得,0ln3)()(23+−−=−xxxxaexhxfx,则3e3ln10xaxxx−
+−,即()3lne3ln10xxaxx−−−−,................................7分令()()3ln0tgxxxx==−>,则()1313xgxxx−=−=,当103x时,(
)0gx<,()gx单调递减,当13x时,()0gx>,()gx单调递增,所以()111lnln3e33tgxg==−=..................................................................
..9分由e10tat−−,即1etta+,令1()(ln3)ttttee+=,则()0ttte−=恒成立,则)(t在)ln3e,+单调递减,所以max2ln3()(ln3)3tee+==,..........................11分所以max2ln3
()3ate+=,因此,a的取值范围是2ln3[,)3e++.............................12分22.(1)令0x=,则23=0tt−−,解得1t=−(舍)或3t=,则4y=−,即(0,4)A−
...................................................................................................................2分令0y=,则22=0tt+−+,解得2t
=或1t=−(舍),则3x=−,即(3,0)B−.....4分1143622SOAOB===;.................................................................................5分(2)由(
1)可知圆心坐标为−−2,23,半径为252)40()30(22=+++则以AB为直径的圆的方程为()22225223=+++yx,即04322=+++yyxx.............
.................................................................................8分由cos,sinxy==可得,以AB为直径的圆的极坐标方程为3cos4sin0++=..
.........................................................................................................................
................10分23.(1)由题知,当1m=时,原不等式即|1||2|5xx++−,.........................................1分当1x−时,
不等式为125xx−−−+,解得21x−−;........................................2分当12x−时,不等式为125xx+−+,恒成立;.........
.........................................3分当2x时,不等式为125xx++−,解得23x,.................................................4分综上
,不等式()5fx的解集为{|23}xx−;...........................................................5分(2)因为|||2||2||3|xmxmxmxmm++−+−+=,当且仅当()(2)
0xmxm+−时不等式取等号,即min()|3|fxm=,............................8分所以31mm−,解得1124mm−或,所以m的取值范围是+
−−,4121,.............................................................10分获得更多资源请扫码加入享学资源网微信公众号www.xi
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