2024届高考数学一轮复习阶段测评卷
(五)导数及其应用
1.函数f(x)?(x2?3x?1)ex的极大值是( ) A.?3e
B.?e2
C.2e2
5D.
e2.若函数f(x)?x3?2lnx?4,则曲线y?f(x)在点(1,f(1))处的切线方程为( ) A.y?x?4
B.y?x?3
C.y?2x?3
D.y?3x?2
3.已知函数f(x)?ex?a(x?1)2?(2a?1)x在(1,2)上单调,则实数的取值范围为( )
?e?1??e2?1??,??A.???,?? ??24?????e?1??e2?1??,??C.???,?? ?2??4???e?1??e2?1??,??B.???,?? ??42?????e?1??e2?1??,??D.???, ??2????4?4.已知函数f(x)?x?lnx,曲线y?f(x)在x?x0处的切线l的方程为y?kx?1,则切线l与坐标轴所围成的三角形的面积为( ) A.
1 2B.
1 4C.2 D.4
5.已知函数f(x)?ex?ax2的图象在(1,f(1))处的切线斜率为e?2,则该切线方程为( ) A.(e?2) x?y?2 e?1?0 C.x?(e?2) y?1?0
B.(e?2) x?y?2 e?3?0 D.(e?2) x?y?1?0
46.已知曲线y?alnx?(x?1)在每一点处的切线的斜率都小于1,则实数a的取值范围是
x( )
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A.(??,5) B.(??,4) C.(??,5] D.(??,4]
7.已知函数f?x?是偶函数,当x?0时,f?x??xlnx?1 ,则曲线y?f?x?在x??1处的切线方程为( ) A.y??x
B.y??x?2
C.y?x
D.y?x?2
8.已知函数f?x??x?lnx,当x2?x1?0时,给出以下几个结论: ①?x1?x2????f?x1??f?x2????0; ②f?x1??x2?f?x2??x1; ③x2?f?x1??x1?f?x2?;
④当lnx1??1时,x1?f?x1??x2?f?x2??2x2?f?x1?. 其中正确的结论有( ) A.0个
B.1个
C.2个
D.3个
9.已知直线y?ax?b(a?R,b?0)是曲线f(x)?ex与曲线g(x)?lnx?2的公切线,则a?b等于( ) A.e?2
B.3
C.e?1
D.2
?x?1?1?10.已知函数f(x)?2x3?ex?e?x,当x?(?1,1)时,f(x?a)?f???0恒成立,则a的取
值范围是( ) A.(??,2]
B.[2,??)
C.(?1,1]
D.(??,1]
11.若函数f(x)?mx2?lnx?1在(1,??)上单调递增,则实数m的取值范围为__________. x12.曲线f(x)?x3?x?2在P0处的切线平行于直线y?4x?1,则P0点的坐标为_________. 13.已知函数f?x??alnx?a?0?,若直线y?x?1与曲线y?f?x?相切,则a?______.
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111?14.已知函数f(x)?ax3?ax2?ex(x?2)?1(a?R)在区间??,2?上有3个不同的极值点,32?2?则实数a的取值范围是_________. 15.已知函数f(x)?mex?x2.
(1)若m?1,求曲线y?f(x)在(0,f(0))处的切线方程;
x(2)若关于的不等式f(x)?x4?me在[0,??)上恒成立,求实数m的取值范围.
??
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答案以及解析
1.答案:D
解析:∵f(x)?(x2?3x?1)ex,
∴f?(x)?(2x?3)ex??x2?3x?1?ex??x2?x?2??ex??x?2??x?1?ex ,
令f??x??0,解得x??1或x?2,
当x??1或x?2时,f??x??0,当?1?x?2时,f??x??0,
2x∴函数f?x??x?3x?1e在???,?1?和?2,???上是增函数,在??1,2?上是减函数,
??∴当x??1时,函数f(x)?(x2?3x?1)ex取得极大值,极大值是f??1??2.答案:A
解析:依题意,可知f'(x)?3x2?故选A. 3.答案:D
5.故选D. e2,故f'(1)?1.而f(1)?5,故所求切线方程为y?x?4.xex?1解析:依题意,f'(x)?e?2a(x?1)?(2a?1).(1)若f'(x)?0在(1,2)上恒成立,则?2a.
xxex?1xex?ex?1(x?1)ex?1令g(x)?,故g'(x)???0,故函数g(x)在(1,2)上单调递增,故
xx2x2e?1ex?1e2?1?a;(2)若f'(x)?0在(1,2)上恒成立,则?a,故实数的取值范围?2a,则
4x2?e?1??e2?1??,??为???,?.故选D. ??42????4.答案:B
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解析:由f(x)?x?lnx得f?(x)?1?11,则f??x0??1?1?k,得x0?, xk?1x011?11kln?0,即k?2,所以切线l的方程为由f?,得??ln??1??k?1k?1k?1?k?1?k?1y?2x?1,
令x?0,得到y??1,令y?0,得到x?B. 5.答案:A
1111,所以所求三角形面积为??|?1|?,故选2224解析:由题可知f?(x)?ex?2ax,f?(1)?e?2a?e?2,所以a?1,故f(1)?e?1,所以函数f(x)的图象在(1,f(1))处的切线方程为y?(e?1)?(e?2)(x?1),即 (e?2)x?y?1?0.故选
A. 6.答案:B
4a44解析:由y?alnx?得y???2,因为曲线y?alnx?(x?1)在每一点处的切线的斜率
xxxxa44都小于1,所以??2?1在(1,??)上恒成立,即a?x?在(1,??)上恒成立.因为当x?1时,
xxx444当且仅当x?,即x?2时等号成立,所以实数a的取值范围是(??,4),x?2x??4,
xxx故选B. 7.答案:A
解析:因为x?0,f?x??f??x???xln??x??1,f??1??1,f'?x???ln??x??1,f'??1???1,所以曲线y?f?x?在x??1处的切线方程为y??x.故选A. 8.答案:C
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