x?x0
2
32
2
⒌下列极限存计算不正确的是( D ).
D. y?ln(1?x)D. y??B. y??xB. f(x)?B. y?xcosx第1章 函数
第2章 极限与连续
C. y?x
x?x0(二)填空题
A. y?x?1
ax?a?x C. y?
2 A. y?ln(1?x)
C. limf(x)?f(x0) ? A. f(x)?(x),g(x)?x
⒋下列函数中为基本初等函数是(C).
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 ).
(一)单项选择题
⒈下列各函数对中,( C )中的两个函数相等.
D. limf(x)?lim?f(x)?高等数学基础第一次作业
x?x0??1,x?0x?0?1,x2,g(x)?xx?x0x2?1 C. f(x)?lnx,g(x)?3lnx D. f(x)?x?1,g(x)?x?1 ⒉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.
x2?9?ln(1?x)的定义域是(3, +∞).⒈函数f(x)?x?32⒉已知函数f(x?1)?x?x,则f(x)? x2 - x .1x)? e1/ 2 .⒊lim(1?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,?x?1,x?0⒌函数y??的间断点是 x=0 .sinx,x?0?x2?1 A. lim2B. limln(1?x)?0x?0x??x?2sinx1?0 C. limD. limxsin?0x??x??xx⒍当x?0时,变量( C )是无穷小量.sinx1A. B.
xx1C. xsin D. ln(x?2)x⒎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??1∴
解: ⒌求⒋求 ⒍求
⒏求
⒎求.
x?x0limf(x)(三)计算题 ⒈设函数 ⒉求函数y?lglg?其连续f(x)??x,上,试将梯形的面积表示成其高的函数.
解:如图梯形面积A=(R+b)h,其中b?x??1??x?1,??x?123?1?x?1x??1解:f(-2) = - 2,f(0) = 0, f(1) = e
A?(R?R2?h2)hsin3xsin3x3x?3lim?limx?0sin2xx?0sin2x222xx??1?2 ⒍若limf(x)?A,则当x?x0时,f(x)?A称为 x2?1x?1lim?lim(x?1)??2x??1sin(x?1)x??1sin(x?1)tan3xsin3xlim?lim3cos3x?3x?0x?0x3x?4?4?42⒐求[(1?)x?6x?8(x?2)(x?4)]2lim2?lim?4x?3?x?4x?5x?x?4?lim?e4(x?1)(x?4)3x??43(1?) ⒑设函数
x?3?(x?2),x?12x?1的定义域.x2x?1?0解得x<0或x>1/2,函数定义域为(-∞,0)∪(1/2,+∞) 解:由x 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blimf(x)?1?f(1)x?1f(x)??1?limf(x)??1?1?0limR2?h2x?31?x2?1(1?x2?1)(1?x2?1)lim?lim2x?0x?0sinx(1?x?1)sinx2(1?x)?1xx?lim?lim?022x?0x?0(1?x?1)sinx1?x?1sinxx?1xx?3?4x?4xlim()?lim()?lim(1?)x??x?3x??x??x?3x?3limf(x)?(1?2)?1?limf(x)?1?不存在,∴函数在x=-1处不连续
?ex,x?0 求:f(?2),f(0),f(1).f(x)??x,x?0?∴函数在x=1处连续
x?1无穷小量 .hRRR讨论f(x)的连续性,并写出
区间.
(二)填空题
⒊曲线f(x)?x(一)单项选择题
(三)计算题
B. 若f(x)在点x0连续,则在点x0可导.
B. ?99D. ?99!第3章 导数与微分
高等数学基础第二次作业
A. 99 C. 99!
⒊设f(x)?e,则lim ⒈设f(0)?0且极限lim ⒍设y?xlnx,则y??? 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连续.
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.
f(1??x)?f(1)?(A).
?x?0?x A. e B. 2e11 C. e D. e24 ⒋设f(x)?x(x?1)(x?2)?(x?99),则f?(0)?(D).
x?1在(1,2)处的切线斜率是 1/2 .π
⒋曲线f(x)?sinx在(,1)处的切线方程是 y=1 .4
2x ⒌设y?x,则y?? 2x2x(lnx+1) .
f(x)f(x)?( B ).存在,则limx?0x?0xxA. f(0) B. f?(0)C. f?(x) D. 0f(x0?2h)?f(x0)⒉设f(x)在x0可导,则lim?(D).
h?02hA. ?2f?(x0) B. f?(x0)C. 2f?(x0) D. ?f?(x0)1?2xsin,x?0? ⒈设函数f(x)??,则f?(0)? 0 .x?x?0?0,df(lnx)x2xx? (2/x)lnx+5/x . ⒉设f(e)?e?5e,则
dx1/x .
⒈求下列函数的导数y?:
⑴y?(xx?3)ex y=(x3/2+3)ex,y'=3/2x1/2ex+(x3/2+3)ex
⑸y?⑼y?esin22⑻y?5sinx⑹y?cose⑸y?cos2ex⑽y?xx?exlnx?x=sinx2⑷y?3x?xsinx?x2⑺y?
3x⑵y?lncosx3
⑵y?cotx?x2lnx y'=-csc2x + 2xlnx +x
⑹y?x4?sinxlnx y'=4x3-cosxlnx-sinx/x
⑶y?xxx y=x7/8 y'=(7/8)x -1/8
xx22x2x21(?2x)sinx?(lnx?x2)cosxxsin2xx2⑶y? y'=(2xlnx-x)/ln2x
lnxcosx?2x⑷y? y'=[(-sinx+2xln2)x3-3x2(cosx+2x)]/x63xy'=[(cosx+2x)3x-(sinx+x2)3xln3]/32x
⑺y?sinnxcosnx y'=nsinn-1xcosxcosnx - nsinnxsin nx
⑾y?xe?ee⒊在下列方程中,y?y(x)是由方程确定的函数,求y?:⑴ycosx?e2y 方程对x求导:y'cosx-ysinx=2 y'e2y
⑵y?cosylnx 方程对x求导:y '= y '(-siny)lnx +(1/x)cosy
x2⑶2xsiny? 方程对x求导:2siny + y'2xcosy=(2xy-x2 y')/y2
yy'=2(xy –y2siny) /(x2+2xy2cosy)
⑹y2?1?exsiny 方程对x求导:2y y'=exsiny + y' excosy
⑷y?x?lny 方程对x求导:y'=1+ y'/y, y'=y /(y-1)
y'= exsiny/(2y- excosy)
y'=ysinx / (cosx-2e2y)
=(3/2x1/2+x3/2+3)ex
y'=[(1/x)cosy] / (1+sinylnx)
=[cosx+2x-(sinx+x2)ln3]/3x
⑻y?extanx?lnx y'=extanx+exsec2x+1/x = ex(tanx+sec2x)+1/x⒉求下列函数的导数y?:⑴y?e1?x
⑺ey?ex?y3 方程对x求导:y'ey =ex -3y2 y', y'=ex/ey+3y2
⑸lnx?ey?y2 方程对x求导:1/x+ y'ey=2y y', y'=1/x(2y-ey)
⑵y?lnxsinx⑶y?arcsin⑵y?xsinx3⑸y?sin2ex⑹y?tanex ⒌求下列函数的二阶导数:⑴y?xlnx⑶y?arctanx1?x1?x1?x⑷y?31?x2⑻y?5x?2y 方程对x求导:y'=5xln5 + y'2yln2, y'=5xln5 /(1-2yln2)⒋求下列函数的微分dy:⑴y?cotx?cscx⑷y?3x(四)证明题
设f(x)是可导的奇函数,试证f?(x)是偶函数.
证明:由 f(x)= - f(-x) 求导f'(x)= - f'(-x)(-x)'f'(x)= f'(-x), ∴f'(x)是偶函数
第4章 导数的应用
高等数学基础第三次作业