2
3
2;196203199
(5)
1511;11511115112222313323314;424311213
12(6)3412(8)34
23412200
34123030
41;2340。04
(7)
解:(1)
cossi
si
22cossi
1。cos
33111003512。1250
11311
(2)2
110200
13
1
(3)第一列乘1加到第二列,并从第二列提取1000,得
34215352153421510002809229092280921000
5212311
1000
342151280921
1
6123000。
(4)从第二行提取2之后,跟第一行互换,得
1
1
1
2251320628。196203199196203199073
(5)把第二、三、四行均加到第一行,并在第一行中提取8,得
8151111151111151123423413412
5111
8511
8151
8111811511341
15111412
1151
111081050
1101100203
1400
1
1040
1
10512。04
11160。04
(6)把第二、三、四行均加到第一行,并在第一行中提取10,得
410101010112341210234123341234
120400
(7)这是一个第二行元素为1、2、3、4的范得蒙行列式,因此
13
f111213
122223
133233
1421314132424312。4243
(8)最后一列乘以1后,加到第一列,并按最后一行展开,得
1234
2200
3030
43020340
2200
3030
4323623020-192。42204203030034
17、解方程
111
(1)1
x
(2)0
x2
2x
x1;1x621111
110。
1
111
解:(1)1
x01x60
2
x1x22x41。x15
即解方程x2x30,因此x3或1。
2
x
(2)0
x
2
11(x2)(x1)0。12x
所以方程的解为:x1或-2。18、设3阶行列式aij1,计算下列行列式:
4a11
(1)4a21
2a123a112a223a212a323a312a123a112a223a212a323a31a12a22a32a13
a13a23;a33a13
2a223a21
(2)2a123a11
4a214a114a314a11
a23a13。a333a113a213a31a13a23a33
4a314a11
解:(1)4a21
2a323a314a112a122a222a32a13a13
4a31a11
8a21
a234a21a334a31a11a11a21a31
a234a21a334a31
a31
a2312a21a33a31
a23-80-8。a33
14
f2a223a21
(2)2a123a11
4a214a114a31
a23
2a22
4a214a114a31
a23
3a21
4a214a114a31
a23a13a33
2a323a31a22
8a12
a132a12a332a32a21a31a21a11a31a23
a133a11a333a31a21a22a12a32a23
a21a11a31a11
a23a33a12a22a32yxyxa13
a1312a11
a32
a138a11a33a31
a13-0a33
8a21
a3r