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函数 极限 连续试题
1.设f(x)?x?x2,求
(1) f(x)的定义域; (2) 12?f[f(x)]?2; (3) limf(x)x?0x.
2.试证明函数f(x)?x3e?x2为R上的有界函数.
3.求lim1n??nln[(1?1n)(1?2n)(1?nn)].
4. 设在平面区域D上函数f(x,y)对于变量x连续,对于变量y 的一阶偏导数有界,试证:f(x,y)在D上连续.
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5.求lim(2x?3x?4x1x?03)x.
1(1?x)x16.求lim[x?0e]x.
7.设f(x)在[?1,1]上连续,恒不为0,求lim31?f(x)sinx?1x?03x?1.
18.求lim(n!)n2n??.
9.设lim(3x??x3?1?ax?b)?2,试确定常数a和b的值.
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10.设函数f(x)=limx2n?1?ax?bn??1?x2n连续,求常数a,b的值.
11.若limsin6x?xf(x)6?f(xx?0x3?0,求lim)x?0x2.
12.设limax?sinxx?0?c(c?0),求常数a,b,c的值. ?xln(1?t3)btdt
13. 判断题:当x?0时,?x1?cost20tdt是关于x的4阶无穷小量.
114. 设a为常数,且lim(ex??x?02?a?arctan1x)存在,求a的值,并计算极限.
ex?1 (共12页) 第3页
215.设lim[ln(1?ex)x?01?a?[x]]存在,且a?N?,求a的值,并计算极限.
ln(1?ex)
16.求limnn??1?an(a?0).
?na?nn17.求limn???b???2??(a?0,b?0). ?
ln(1?f(x)18.设limsin2x)x?03x?1=5,求limf(x)x?0x2.
19.设f(x)为三次多项式,且xlimf(x)f(x)f?2ax?2a?xlim?4ax?4a?1,求xlim(x)?3ax?3a的值.
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24.设连续函数f(x)在[1,??)上是正的,单调递减的,且
dn??f(k)??f(x)dx,试证明:数列?dn?收敛.
nn
20.设x?1,求lim(1?x)(1?x2)(1?x4nn??)(1?x2).
21.试证明:(1) ?(?1n111?1+n)?1???为递减数列;(2) n?1?ln(1?n)?n,n?1,2,3,.
limnn22.求n??3nn!.
23.已知数列:a111?2,a2?2?2,a3?2?,
2?12a4?2?12?1的极限存在,求此极限.
2?12
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k?11
25.设数列?xn?,x0?a,x1?b,求limn??xn.
26.求lima2nn??1?a2n.
28.求lim(6x6x????x5?6x6?x5).
x1n?2(xn?1?xn?2)(n?2),
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29.设函数f(x)是周期为T(T?0)的连续函数,且f(x)?0,试证:
xlim1x???x?0f(t)dt?1T?T0f(t)dt.
30.求lim?11n??0xdx.
en(1?x)nn
31.设lim(1?x)?x???tetx??x??dt,求?的值.
32.判断函数f(x)?limxn?1n??xn?1的连续性.
33.判断函数f(x)=x2?x1x2?11?x2的无穷间断点的个数.
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34.设f(x)为二次连续可微函数,f(0)=0,定义函数
?g(x)??f?(0)当x?0?,试证:g(x)?f(x)?x当x?0连续可微.
35.设f(x)在[a,b]上连续,f(a)?f(b),对x?(a,b),
g(x)?limf(x?t)?f(x?t)t?0t存在,试证:存在c?(a,b),使g(c)?0.
36.若f(x)为[a,b]上定义的连续函数,如果?ba[f(x)]2dx?0,试证:
f(x)?0(a?x?b).
37.设函数f(x)在x=0处连续,且limf(2x)?f(x)x?0x?A,试证:f?(0)=A.
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38.设f(x)在[a,b]上二阶可导,过点A(a,f(a))与B(b,f(b))的直线与曲线
y?f(x)相交于C(c,f(c)),其中a?c?b.试证:至少存在一点??(a,b),
使得f??(?)=0.
39.设f(x),g(x),h(x)在a?x?b上连续,在(a,b)内可导,试证:
f(a)g(a)h(a)至少存在一点??(a,b),使得f(b)g(b)h(b)=0,并说明拉格朗日中值 f?(?)g?(?)h?(?)定理和柯西中值定理是它的特例.
40.试证明函数y?sgnx在x?[?1,1]上不存在原函数.
41.设函数f(x)=limn3nn??x?1,试判断f(x)的不可导点的个数.
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42.设f(x)=sinx?sinx?sinx?(0?x??2),求f?(x).
43.设x2n?1?3xn?xn(n?1,2,3,),0?x1?3,试说明数列?xn?的极限存在.
?x?044.求函数f(x)=??sin1?x2?1?x(??2x)的间断点.
??2cosxx?0
45.求曲线??13???的斜渐近线.
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??1?46.求数列?nn?的最小项.
?? 50.求lim x.
x?0 sin1x47.求limtan(tanx)?sin(sinx) x?0tanx?sinx.
48.设f(x)在[0,2]上连续,在(0,2)内有二阶导数,且limf(x)x?1(x?1)2?1, ?21f(x)dx?f(2),试证:存在??(0,2),使得f??(?)=(1+??1)f?(?).
49.试证:若函数f(x)在点a处连续,则函数f+(x)=max?f(x),0?与
f-(x)=min?f(x),0?在点a处都连续.
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