2024年浙江专升本高数考试真题答案
一、选择题:本大题共5小题,每小题4分,共20分。
?sinx,x?0?1、设f(x)??x,则f(x)在(?1,1)内( C )
,x?0??xA、有可去间断点
x?0x?0B、连续点
x?0 C、有跳跃间断点
x?0D、有第二间断点
f(x)?limx?0,limf(x)?lim解析:lim????x?0x?0sinx?1 x?limf(x)?limf(x),但是又存在,?x?0是跳跃间断点 ??22、当x?0时,sinx?xcosx是x的( D )无穷小 A、低阶 解析:lim B、等阶 C、同阶 D、高阶 sinx?xcosxcosx?cosx?xsinxsinx?lim?lim?0?高阶无穷小 2x?0x?0x?0x2x2x?x03、设f(x)二阶可导,在x?x0处f??(x0)?0,limA、取得极小值 解析:?limx?x0f(x)则f(x)在x?x0处( B ) ?0,x?x0D、x0,f(x0)是拐点 B、取得极大值 C、不是极值 ??f(x)?f(x0)f(x),则其f?(x0)?0,f(x0)?0, ?0,?f?(x0)?limx?x0x?x0x?x0x0为驻点,又?f??(x0)?0?x?x0是极大值点。 4、已知f(x)在?a,b?上连续,则下列说法不正确的是( B ) A、已知?baf2(x)dx?0,则在?a,b?上,f(x)?0 d2xf(t)dt?f(2x)?f(x),其中x,2x??a,b? B、dx?xC、f(a)?f(b)?0,则?a,b?内有?使得f(?)?0 D、y?f(x)在?a,b?上有最大值M和最小值m,则m(b?a)?解析:A.由定积分几何意义可知,f(x)?0,的面积,该面积为
0?2?baf(x)dx?M(b?a)
?baf2(x)dx为f2(x)在?a,b?上与x轴围成
f(x)满足
f2(x)?0,事实上若
?连续?非负?f(x)?0(a?x?b) ??bf(x)dx?0??ad2xf(x)dx?2f(2x)?f(x) B.
dx?xC. 有零点定理知结论正确
D. 由积分估值定理可知,x??a,b?,m?f(x)?M, 则
?mdx??abbaf(x)dx??Mdx?m(b?a)??f(x)dx?M(b?a) aabb5、下列级数绝对收敛的是( C ) ???cosn(?1)n?1(?1)n?11A、? B、? C、? D、? n?1n?1nn?1n?1n?1ln(n?1)n3?9?解析:A.limn??1?11n?1?1,由?发散发散 ?1n?1nn?1n1??11ln(1?n)1nB. lim发散 ?lim?lim?0,由?发散??n??n??n??1nln(1?n)n1?nn?1n?1ln(1?n)1C.
cosn?211cosnn?9,而lim=1,由?3收敛?收敛??22n??1n?1n?9n2?9n2?9n?92n3n21收敛 D.
1发散 ?nn?11x?二、填空题 6、lim(1?asinx)?e x?0a解析:lim(1?asinx)?limex?0x?01x1ln(1?asinx)x?eln(1?asinx)limx?0x?e1?acosxlim1?asinxx?01?ea
7、limx?0f(3)?f(3?2x)3?3,则f?(3)?
sinx2x?0解析:limf(3)?f(3?2x)f(3?2x)?f(3)?2lim?2f?(3)?3
x?0sinx?2x
sinx(cosx?b)?5,则b??9
x?0e2x?asinxx(cosx?b)(cosx?b)?lim?5 解析:lim2x2xx?0ex?0?ae?a8、若常数a,b使得lim所以根据洛必达法则可知:1?a?0,a?1
x(cosx?b)cosx?b1?b?lim?
x?0x?02x221?b?5,b??9 2lim9、设??x?ln(1?t)dy,则dx?y?t?arctantdy?dtdxdxdtdy1?t?1?1 解析:121?t2?t(1?t),dy1dx1?t21?t2t?1?1 d2yy2?x210、y?f(x)是x?y?1?0所确定的隐函数,则2? 3dxy2解析:方程两边同时求导,得:2x?2yy??0,y??x, yx带入, y方程2x?2yy??0同时求导,得:1?(y?)2?yy???0,将y??x2d2y1x2y2?x2则得,1?()?yy???0,2?y????3? ydxyyy311、求y?x的单增区间是(?1,1) 21?x1?x2?2x21?x2解析:y?? ?2222(1?x)(1?x)2令y??0,则x?1,?1?x?1 12、求已知
?1kf(x)dx?e?C,则lim??f()? e?1
n??nk?0nx2n?1111kx21解析:lim??f()??f(x)dx??f(x)dx?(e?C)0?e?1
00n??nk?0nn?113、
???e1dx?1
x(lnx)2
解析:
???e??111dx?dlnx???e(lnx)2x(lnx)2lnx??e?1
14、由y?x2:y?1,x?2围成的图形面积为
4 3解析:A??21142(x2?1)dx?(x3?x)1?
3315、常系数齐次线性微分方程y???2y??y?0的通解为y?(C1?C2x)ex(C1C2为任意常数) 解析:特征方程:r?2r?1?0,特征根:r1?r2?1 通解为y?(C1?C2x)ex(C1C2为任意常数) 三、计算题 (本大题共8小题,其中16-19小题每小题7分,20-23小题每小题8分,共60分) 2ex?e?x16、求lim x?0ln(1?sinx)ex?e?xe2x?12x2x?x解析:lim?lime?lim?lim?2 x?0ln(1?sinx)x?0ln(1?sinx)x?0sinxx?0x17、设y(x)?(1?sinx),求y(x)在x??处的微分 解析:y(x)?(1?sinx) xxlny?xln(1?sinx) 1cosxy??ln(1?sinx)?xy1?sinx dy?[ln(1?sinx)?xcosx](1?sinx)xdx 1?sinx将x??代入上式,得微分dy???dx 18、求解析:
??5?05?1?cos2xdx
1?cos2xdx??|sinx|dx02?3?5π0??sinxdx??(?sinx)dx??sinxdx??(?sinx)dx??sinxdx0π
4?5??2?3?4?
2?3?4?5???cosx|??cosx|?cosx|?cosx|?cosx|0?2?3?4??10
19、求arctan?xdx
2令x?t,则x?t解析:,dx?2tdt
?arctantdt2?t2arctant??t2darctant?t2arctant??t221dt1?t2
1?t2?1?tarctant??dt1?t2 ?t2arctant??(1?1)dt1?t2
?t2arctant?t?arctant?c则原式?xarctanx?x?arctanx?c 20、(-1?1xxcosx?)dx 45?4x1?xxcosx1?x4为奇函数, 解析:??该式不代入计算 5?t2令t?5?4x,则x?4 1dx??tdt 25?t211该式??(?t)dt 34t2113??(5?t2)dt 811113?(5t?t3)|1? 36 8?2x?b,x?021、已知f(x)??在x?0处可导,求a,b
?ln(1?ax),x?0解析: