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函数 极限 连续试题
1.
设f(x)
求
(1) f(x)的定义域; (2) 12f[f(x)]2
; (3) lim
f(x)x0x
.
2.试证明函数f(x)x3ex2
为R上的有界函数.
3.求lim1nnln[(11n)(12
n)
(1nn
)].
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.
(共12页)第1页
5.求lim(
2x3x4x1
x03
)x.
1(1x)x
6.求lim[
x0e]x.
7.设f(x)在
[1,1]上连续,恒不为0,求x0
8.求lim(n!)n2
n
.
9.设x
axb)2,试确定常数a和b的值.
(共12页)第2页
10.设函数f(x)=limx2n1axb
n1x
2n连续,求常数a,b的值.
11.若limsin6xxf(x)6f(xx0x30,求lim)
x0x2
.
12.设lim
axsinx
x0c(c0),求常数a,b,c的值.xln(1t3)btdt
13.判断题:当x0时,x
1cost2
0t
是关于x的4阶无穷小量.
114.设a为常数,且lim(
ex
x0
2aarctan1
x
)存在,求a的值,并计算极限.
ex1
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215.设lim[
ln(1ex
)x0
1a[x]]存在,且aN,求a的值,并计算极限.
ln(1ex
)
16.
求n(a0).
n
17.
求limn2(a0,b0).
ln(1
f(x)
18.设lim
)
x0
3x1
=5,求limf(x)x0x2.
19.设f(x)为三次多项式,且xlim
f(x)f(x)f2ax2axlim4ax4a1,求xlim(x)
3ax3a
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
dnf(k)f(x)dx,试证明:数列dn收敛.
n
n
20.设x1,求lim(1x)(1x2)(1x4n
n
)
(1x2).
21.试证明:(1) (1n1111+n)1
为递减数列;(2) n1ln(1n)n,n1,2,3,.
limnn
22.求n3nn!
.
23.已知数列:a1
112,a222
,a32
,
22
a42
12
1的极限存在,求此极限.
22
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k1
25.设数列xn,x0a,x1b,求limn
xn.
26.求lima2n
n1a2n
.
28.
求limx
.
x1
n2
(xn1xn2)(n2),
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29.设函数f(x)是周期为T(T0)的连续函数,且f(x)0,试证:
xlim1xx0f(t)dt1TT0f(t)dt.
30.求lim1
1n0
x.
en
(1x)n
n
31.设lim(
1x)x
tetxx
dt,求的值.
32.判断函数f(x)limxn1
nxn1
的连续性.
33.
判断函数f(x.
(共12页)第7页
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x0,试证:g(x)f(x)
x当x0连续可微.
35.设f(x)在[a,b]上连续,f(a)f(b),对x(a,b),
g(x)lim
f(xt)f(xt)
t0
t
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b
a[f(x)]2dx0,试证:
f(x)0(axb).
37.设函数f(x)在x=0处连续,且lim
f(2x)f(x)
x0
x
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
yf(x)相交于C(c,f(c)),其中acb.试证:至少存在一点(a,b),
使得f()=0.
39.设f(x),g(x),h(x)在axb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ysgnx在x[1,1]上不存在原函数.
41.
设函数f(x)=nf(x)的不可导点的个数.
(共12页)第9页
42.
设f(x(0x
),求f(x).
43.
设xn1(n1,2,3,),0x13,试说明数列xn的极限存在.
x0
44.求函数f(x)=sin1
x21
x(2x)的间断点.
2cosx
x0
45.求曲线
3
的斜渐近线.
(共12页)第10页
1
46.求数列nn的最小项.
50.求lim
x.
x0
sin1
x
47.求limtan(tanx)sin(sinx)
x0tanxsinx
.
48.设f(x)在[0,2]上连续,在(0,2)内有二阶导数,且lim
f(x)
x1(x1)2
1,
f(x)dxf(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)=maxf(x),0与
f-(x)=minf(x),0在点a处都连续.
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