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高等数学基础形考作业1答案:
第1章 函数 第2章 极限与连续
(一)单项选择题
⒈下列各函数对中,(C)中的两个函数相等.
2 A. f(x)?(x),g(x)?x B. f(x)?x2?1 B. limln(1?x)?0 A. lim2x??x?2x?0x2,g(x)?x
sinx1?0 D. limxsin?0
x??x??xx⒍当x?0时,变量(C)是无穷小量.
sinx1 A. B.
xx1 C. xsin D. ln(x?2)
x C. lim⒎若函数f(x)在点x0满足(A),则f(x)在点x0连续。
A. limf(x)?f(x0) B. f(x)在点x0的某个邻域内有定义
x?x0x2?1 C. f(x)?lnx,g(x)?3lnx D. f(x)?x?1,g(x)?
x?13⒉设函数f(x)的定义域为(??,??),则函数f(x)?f(?x)的图形关于(C)对称. A. 坐标原点 B. x轴 C. y轴 D. y?x ⒊下列函数中为奇函数是(B).
A. y?ln(1?x) B. y?xcosx
2 C. lim?f(x)?f(x0) D. lim?f(x)?lim?f(x)
x?x0x?x0x?x0
(二)填空题
⒈函数f(x)?x2?9?ln(1?x)的定义域是?3,???.
x?32ax?a?x C. y? D. y?ln(1?x)
2 ⒋下列函数中为基本初等函数是(C). A. y?x?1 B. y??x C. y?x2⒉已知函数f(x?1)?x?x,则f(x)? x
2
-x .
1x⒊lim(1?)?e2. x??2x1?x?⒋若函数f(x)??(1?x),x?0,在x?0处连续,则k? e .
?x?0?x?k,1??1,x?0 D. y??
1,x?0?⒌下列极限存计算不正确的是(D).
⒌函数y???x?1,x?0的间断点是x?0.
?sinx,x?0可编辑
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⒍若limf(x)?A,则当x?x0时,f(x)?A称为x?x?x0x0时的无穷小量。
AE?OA2?OE2?R2?h2
则上底=2AE?2R2?h2 (三)计算题
⒈设函数
?e,x?0 f(x)???x,x?0求:f(?2),f(0),f(1).
解:f??2???2,f?0??0,f?1??e?e
1xh2R?2R2?h2?hR?R2?h2 2sin3x⒋求lim.
x?0sin2xsin3xsin3x?3xsin3x3133解:lim?lim3x?lim3x?=??
x?0sin2xx?0sin2xx?0sin2x2122?2x2x2x故S?????⒉求函数y?lg2x?1的定义域. x?2x?1??x?0??2x?11?解:y?lg有意义,要求?解得?x?或x?0
x2??x?0???x?0? 则定义域为?x|x?0或x?x2?1⒌求lim.
x??1sin(x?1)x2?1(x?1)(x?1)x?1?1?1?lim?lim???2 解:limx??1sin(x?1)x??1sin(x?1)x??1sin(x?1)1x?1??1?? 2?⒊在半径为R的半圆内内接一梯形,梯形的一个底边与半圆的直径重合,另一底边的两个端点在半圆上,试将梯形的面积表示成其高的函数. 解: D A R
O h E
B C 设梯形ABCD即为题中要求的梯形,设高为h,即OE=h,下底CD=2R 直角三角形AOE中,利用勾股定理得
tan3x.
x?0xtan3xsin3x1sin3x11解:lim?lim?lim??3?1??3?3
x?0x?0xxcos3xx?03xcos3x1⒍求lim1?x2?1⒎求lim.
x?0sinx1?x2?1(1?x2?1)(1?x2?1)x2?lim?lim解:lim2x?0x?0x?0sinx(1?x?1)sinx(1?x2?1)sinx ?limx?0
x(1?x2?1)sinxx?0?0
1?1?1??⒏求lim(x??x?1x). x?3可编辑
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1?1解:lim(x?1(1?1)x[(1?1)?x]?11xxe??4x??x?3)?lim(xx??)?limx?lim?x1?3x??(1?3)xx??x?3?e [(1?1)3]3exxx3⒐求limx2?6x?8x?4x2?5x?4.
x2解:lim?6x?8?x?4??x?2??1??limx?2x?4x?1?4?24?1?2x?4x2?5x?4?limx?4?x?4??x3
⒑设函数
?(x?2)2,x?1f(x)???x,?1?x?1
??x?1,x??1讨论f(x)的连续性。
解:分别对分段点x??1,x?1处讨论连续性 (1)
xlim??1?f?x??xlim??1?x??1limf?x??
x??1?xlim??1??x?1???1?1?0所以xlim??1?f?x??xlim??1?f?x?,即f?x?在x??1处不连续 (2)
xlim?1?f?x??lim?x?2?2??1?2?2x?1??1xlim?1?f?x??xlim?1?x?1
f?1??1所以limx?1?f?x??limx?1?f?x??f?1?即f?x?在x?1处连续
由(1)(2)得f?x?在除点x??1外均连续
高等数学基础作业2答案:
第3章 导数与微分
(一)单项选择题
⒈设f(0)?0且极限limf(x)f(x)x?0x存在,则limx?0x?(C).
A. f(0) B. f?(0) C. f?(x) D. 0cvx ⒉设f(x)在xf(x0?2h)?f(x0)0可导,则limh?02h?(D).
A. ?2f?(x0) B. f?(x0) C. 2f?(x0) D. ?f?(x0)
⒊设f(x)?ex,则f(1??x)?f(1)?limx?0?x?(A).
A. e B. 2e C. 112e D. 4e
⒋设f(x)?x(x?1)(x?2)?(x?99),则f?(0)?(D).
A. 99 B. ?99 C. 99! D. ?99! ⒌下列结论中正确的是(C).
A. 若f(x)在点x0有极限,则在点x0可导. B. 若f(x)在点x0连续,则在点x0可导.
可编辑
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C. 若f(x)在点x0可导,则在点x0有极限. D. 若f(x)在点x0有极限,则在点x0解:y???cotx??????x2?lnx?x2?lnx???csc2x?x?2xlnx
连续.
(二)填空题
? ⒈设函数f(x)???x2sin1,x?0,则f?(0)? 0 . ?x?0,x?0 ⒉设f(ex)?e2x?5ex,则
df(lnx)2lnx5dx?x?x。
⒊曲线f(x)?x?1在(1,2)处的切线斜率是k?
1
2
。 ⒋曲线f(x)?sinx在(π2,1)处的切线方程是y?1。 ⒌设y?x2x,则y??2x2x(1?lnx) ⒍设y?xlnx,则y???1x。 (三)计算题
⒈求下列函数的导数y?:
⑴y?(xx?3)ex
31 解:y???xx?3??ex??xx?3??ex?? ?(x2?3)ex?3x2x2e
⑵y?cotx?x2lnx
⑶y?x2lnx
?x2??lnx2?解:y???x?lnx?ln2x?2xlnx?xln2x
?cosx?2x⑷yx3 x3x3解
y???cosx?2??x??:
??cosx?2??x?x3?2?x(?sinx?2xln2)?3(cosx?2x)x4 ⑸y?lnx?x2sinx
解
:
?sinx??lnx?x2??sinx??sinx(1?2x)?(lnx?x2)cosxy???lnx?x2?sin2x?xsin2x ⑹y?x4?sinxlnx
解:y???x4????sinx??lnx?sinx?lnx???4x3?sinxx?cosxlnx y?sinx?x2⑺3x
可编辑
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解:
2x2x???sinx?x?3??sinx?x??3?3x(cosx?2x)?(sinx?x2)3xln32?y?cosx?2x?2xcosx 解:
y???3x?2?32x⑻y?extanx?lnx
解:y???ex??tanx?ex?tanx????lnx???extanx?excos2x?1x ⒉求下列函数的导数y?: ⑴y?ex
解:y???ex??1??ex??1x?2?1ex22x ⑵y?lncosx
解:
y??1cosx??sinx???sinxcos??tanx ⑶y?xxx
???7??1解:y??x8??7??88x
??⑷y?sin2x
解:y??2sinx?sinx???2sinx?cosx?2sin2x
⑸y?sinx2
2⑹
y?cosex
y???sinex22解:?ex2????2xexsinex2
⑺y?sinnxcosnx
解y???sinnx??cosnx?sinnx?cosnx???nsinn?1xcosxcosnx?nsinnxsin(nx)
⑻y?5sinx
解:y??5sinxln5?cosx?ln5cosx5sinx
⑼y?ecosx
解:y??ecosx??sinx???sinxecosx
⒊在下列方程中,y?y(x)是由方程确定的函数,求y?:⑴ycosx?e2y
解:y?cosx?ysinx?2e2yy? y??ysinxcosx?2e2y ⑵y?cosylnx
解:y??siny.y?lnx?cosy.1x y??cosyx(1?sinylnx)可编辑
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