经济数学基础形成性考核册参考答案
部分题目与答案符号在预览界面看不清,下载后再打开就可以看清了 作业一
(一)填空题 1.limx?0x?sinx?___________________.答案:0 x?x2?1,x?02.设f(x)??,在x?0处连续,则k?________.答案:1 ?k,x?0?3.曲线y?x+1在(1,2)的切线方程是 .答案:y?11x? 2224.设函数f(x?1)?x?2x?5,则f?(x)?____________.答案:2x
5.设f(x)?xsinx,则f??()?__________.答案:?(二)单项选择题
1. 当x???时,下列变量为无穷小量的是(D)
π2π 2x2A.ln(1?x) B.
x?1C.e?1x2 D.
sinx x2. 下列极限计算正确的是(B) A.limxxx?0?1 B.lim?x?0xx?1
C.limxsinx?01sinx?1 D.lim?1
x??xx3. 设y?lg2x,则dy?(B). A.
11ln101dx B.dx C.dx D.dx 2xxln10xx4. 若函数f (x)在点x0处可导,则( B )是错误的.
A.函数f (x)在点x0处有定义 B.limf(x)?A,但A?f(x0)
x?x0 C.函数f (x)在点x0处连续 D.函数f (x)在点x0处可微 5.若f()?x,f?(x)?(B).
1xA.
1111 B. C. D. ??xxx2x2(三)解答题
1.计算极限
x2?3x?21x2?5x?61?? (2)lim2? (1)lim2x?1x?22x?1x?6x?822x2?3x?511?x?11?? (4)lim2? (3)limx?0x??x23x?2x?43x2?4sin3x3?4 (5)lim? (6)limx?2x?0sin5xsin(x?2)51?xsin?b,x?0?x?2.设函数f(x)??a,x?0,
?sinxx?0?x?问:(1)当a,b为何值时,f(x)在x?0处有极限存在? (2)当a,b为何值时,f(x)在x?0处连续.
答案:(1)当b?1,a任意时,f(x)在x?0处有极限存在; (2)当a?b?1时,f(x)在x?0处连续。 3.计算下列函数的导数或微分: (1)y?x?2?log2x?2,求y? 答案:y??2x?2ln2?(2)y?x2x21 xln2ax?b,求y?
cx?dad?cb 2(cx?d)答案:y??(3)y?13x?5,求y?
答案:y???32(3x?5)3
(4)y?x?xex,求y?
答案:y??12xax?(x?1)ex
(5)y?esinbx,求dy
ax答案:dy?e(asinbx?bcosbx)dx (6)y?e?xx,求dy
1x311x?2ex)dx 答案:dy?(2x(7)y?cosx?e?x,求dy 答案:dy?(2xe?x?n22sinx2x)dx
(8)y?sinx?sinnx,求y? 答案:y??n(sinn?1xcosx?cosnx)
(9)y?ln(x?1?x2),求y? 答案:y??11?xsin1x2
(10)y?21?3x2?2x,求y? ?x1x答案:y???2sinln2x25?11?31cos?x2?x6
x264.下列各方程中y是x的隐函数,试求y?或dy (1)x?y?xy?3x?1,求dy 答案:dy?22y?3?2xdx
2y?xxy(2)sin(x?y)?e?4x,求y?
4?yexy?cos(x?y)答案:y?? xyxe?cos(x?y)
国家开放大学2020年秋季学期电大考试经济数学考题题库及答案



