1?x111a211?x11b2 5) 6)2111?y1c1111?yd21000427327?a?1?2?b?1?2?c?1?2?d?1?2?a?2?2?b?2?2?c?2?2?d?2?2?a?3?2?b?3?2?c?3?2?d?3?2
11327 解:1) 原式=2000543443?10521443
1000721621116211327??294?105 . =10511443??1051621016212x?2yyx?yxx?yxy1yx?y?y ?x01327 2)原式=2x?2y2x?2y =2(x?y)?2(x?y)0x0x?yx?y??2x3?y3 .
x?y?x??663)原式=
661311113123411111102?610030034121102010?6?8?48 . 021010 4) 原式=
1010412341011?3 ?10202?2?230?1?1?1?3?22?4?160 .
=200?22?20000?4xx00x00011?x111?x105)原式= ?00yy00y01111?y101?y
(行列式第6页)
a2b26)原式=2cd22a?12a?32a?52b?12b?32c?12c?3a22a?1222b?122
2c?1222d?1222b?5b2?22c?5cd22d?12d?32d?5 =0 .
14.证明
b?cc?ac1?a1c2?a2a?babb1b2cc1 c2 b1?c1b2?c2a1?b1?2a1a2?b2a2 证明:由行列式的性质,有
a?b?cc?ac1?a1c2?a2?b?b1?b2a?ba1?b1 a2?b2?c?c1 ?c2 左边=2a1?b1?c1a2?b2?c2a?b?c =2a1?b1?c1a2?b2?c2abb1b2c =2a1a2 即证.
c1?右边 . c2 15.算出下列行列式的全部代数余子式:
120?1 1)
0000 解:1)
122041?121 2)321 10143 (行列式第7页)
A11??6, A12?0, A13?0,A14?0 A21??12, A22?6,A23?0,A24?0
A31?15,A32??6,A33??3,A34?0A41?7,A42?0,A43?1,A44??2 .
2)A11?7,A12??12,A13?3 A21?6,A22?4,A23??1 A31??5,A32?5,A33?5 . 16.计算下面的行列式:
112111121112 1)
141123111?1?3 2)3125?321?11?12102
012?1421231201 3)?135323110212 4)315?1112121?101213012001?120 212111111110?1?1?50115 解:1)原式= ??0114000?10?1?2?300?12 (行列式第8页)
10 =
00111115?1 .
0?1200?111222?1203331?1 2)原式=
121?3424211?11211?330602?12034 11 =-
1164 12?3211?24?6?36?54?3?32???13 . 1212 =-
0121?1?12454203)原式=?10320?50?221211?1?14?10?10?
3?55?11?112?2411421 =-13612116?91930006?9?1315?6?25310
015?6683683083 =3
1930??483 .
612102?211102102?2131624 21320?1124)原式=6481?10426220?110?1040821?1011620(行列式第9页)
211104 =
81?116222?223412?128361312712?20?512
03002170127012 =-
13812?51232330??010??010
88171001710017 =-
37123? .
810178 17.计算下列n阶行列式:
x00?0yyx0?000?00y?00x?00???0????a1?b1a1?b2?a1?bna2?b1?an?b1a2?b2?a2?bn
???an?b2?an?bn 1) 2)
0?0xx2?xnxn?122?2222?2 4)223?2
?????222?nx1?m 3)
x1?x1x2?m???x2?xn?m10?0022?0030?00?n?1??00?n00?01?1 5)
?2?
?2?n?n?11?nn?1 解:1)按第一列展开,原式=xn???1? 2)从第2列起各列减去第1列 (行列式第10页)
yn.