第1章1.(1)3;(2)1;(3)0;(4)0;(5)4;(6)(c-b)(c-a)(b-a)2.(1)4,偶;(2)5,奇;(3)(1)2nn,当4nk,41k时,偶;当42nk,43k时,奇;(4)(1)2nn,当4nk,43k时,偶;当41nk,42k时,奇;3.!2n.4.(132645)3,(314256)3,符号为正.5.(13254)2,为使符号为正,(431)ij要为偶数,因为(54231)7,(24531)6,故2i,5j.6.(1)(1324)(1)Dabcdabcd.(2)(121)1(1)!(1)!nnnDnn.(3)0.7.通过行列式的定义证明,略.8.略.9.(1)3a;(2)27a;(3)-3a.10.(1)1(1)nnnab.(2)2(2)!n.(3)(4)例题(5)1112121()(1)nnnniiiiiiiiiiaxDxxaaxxx.(6)2221211222222222(1)(1)()nnnnnnDaDbDabD2212()nabD,又222abDabba,则有222()nnDab.(7)(1)2111()()(1)!nnnijjinjiniDxxjii(8)0,22,21,1nDnn(9)1nnnkkkDxax,2n.(10)20nkkDx,2n.11.(1)例题11x,22x,33x.(2)(2)()()aabcxcaba,2()()bcaycbba,2()()abczcacb.12.当0D时,即2(1)4ab时.13.(1)无解.(2)18x,23x,36x,40x.(3)选取3x和4x为自由变量,则3xa,4xb,11(13)14xab,21(55)14xab.(4)选取3x和4x为自由变量,则3xa,4xb,2332xab,1223xab.14.当0a,2b时,线性方程组有解,转化为:1234523451,2263,xxxxxxxxx取3xa,4xb,5xc为自由变量,解得3xa,4xb,5xc,23226xabc,152xabc.15.当0和1时,无解.当0或1时,有解.取3xa,4xb,则22xba,144xab.