正文:
经济数学基础形成性考核册参考答案
经济数学基础作业1
一、填空题:
1.0 2.1 3.x?2y?1?0 4.2x 5.二、单项选择:
1.D 2.B 3.B 4.B 5.C 三、计算题: 1、计算极限 (1) 原式?limx?1?2
(x?1)(x?2)(x?1)(x?1)?limx?1x?2x?1
??12(x-2)(x-3)(x-2)(x-4)x?2(2). 原式=lim?lim
x?3x?412(1?x?1)(1?x?1)x(1?x?1)x?0
x?2
?(3). 原式=lim =lim =?
?11?x?1x?0
12 1?3x3x??52x=1 432 (4).原式=
3?xsin3x (5).原式=
35limx?03x sin5x5x
=
35
x?2sin(x?2)x?2lim(x?2) (6). 原式=limx?2
=
x?2limx?2sin(x?2)x?2
= 4
2.(1)limf(x)?b,x?0?limf(x)?1
x?0?当 a?b?1时,(2). 当有limf(x)?f(0)?1
x?0a?b?1时,有limf(x)?f(0)?1
x?0 函数f(x)在x=0处连续. 3. 计算下列函数的导数或微分 (1). y??2x?2ln2? (2). y??x1xln22 ?ad?bc(cx?d)2a(cx?d)?c(ax?b)(cx?d)32
(3). y??? (4). y?? =
12x321(3x?5)x?
x2x?(e?xe)
xx?e?xe
axy??(e)?(sinbx?eaxax(sinbx)?cosbx (5). ∵ ?ae?eaxaxsinbx?beax
(sinbx?bcosbx) ∴dy?e(asinbx?bcosbx)dx (6). ∵y??? ∴dy?(321x21ex?1x2321x
x?ex)dx
(7).∵y???sin =?sin2xsin2x?(xx)??e?x2?x2?(?x)?
2?2xexx
?x2 ∴dy?(??2xe)dx
(8) y??nsin(9) y??x?n?1x?cosx?ncosnx
211?x1x?1?x1x?1?x22?(x?1?x)? x1?x22 =?(1?1?x2)
=
1??x2
1?x =
21?xy??2cos1x?ln2?(cos?2cos1x1x)??(x1x??121?x6?1?2)?15(10)
??1x2
ln2?sinx6x2. 下列各方程中y是x的隐函数,试求y?或dy
23(1) 方程两边对x求导:
2x?2y?y??y?xy??3?0 (2y?x)y??y?2x?3 所以 dy?y?2x?32y?xdx
(2) 方程两边对x求导: cos(x?y)(1?y?)?e [cos(x?y)?xe 所以 y??xyxy?(y?xy?)?4
xy]y??4?cos(x?y)?yexyxy
4?cos(x?y)?yecos(x?y)?xe
3.求下列函数的二阶导数:
2x (1) y?? 21?x y???2(1?x)?2x?2x(1?x)?121222??2?2x222(1?x)32
(2) y??(x y???34x?x2)????1412x?12x?12?5214x?32
y?(1)?
34??1
经济数学基础作业2
一、填空题:
1.2ln2?2 2. sinx?c 3. ?二、单项选择:
1.D 2.C 3.C 4.D 5.B 三、计算题: 1、计算极限
3x (1) 原式=?()dx
e3x()x3 =e?c?x?c
3e(ln3?1)lnex12F(1?x)?c 4. 0 5. ?211?x2
(2) 原式=?(x1?123?2x?x2)dx
3 =2x2?43x2?25125x2?c x?2x?c ??1222 (3) 原式=?(x?2)dx? (4) 原式=? (5) 原式= =
1212?d(1?2x)1?2x2ln1?2x?c
?2?xd(2?x)
3213(2?x)2?c
(6) 原式=2?sinxdx??2cosx2x?c
(7) ∵(+) x sin x2x2 (-) 1 ?2cos (+) 0 ?4sin∴原式=?2xcosx x?c
22 (8) ∵ (+) ln(x?1) 1 ?4sin (-) ?1x?1 x
∴ 原式=xln(x?1)? =xln(x?1)??xx?1dx 1)dx
x?1 =xln(x?1)?x?ln(x?1)?c
?(1? 2.计算下列定积分:
(1) 原式=?(1?x)dx??11?21(x?1)dx
52?92 =2?(112x?x)1?2?1x122
(2) 原式=?2exx121(?x)d212
=?exe3?e?e2 x(3) 原式=?1d(1?lnx)
x1?lnx =21?lnxe31?2
(4) ∵ (+)x cos2x (-)1 12sin2x
(+)0 ?∴ 原式=(12xsin2x??1??14cos2x
?141cos2x)02
=?1442(5) ∵ (+) lnx x
(-) ∴ 原式= =
e12221x e1x22
xlnx?1?214e1xdx
22?14x2e14?(e?1)
(6) ∵原式=4??0xe?xdx
?x又∵ (+)x e
(-)1 -e (+)0 e?x?x