入-i01-1-r1721112rA-2> - 12..0X21132127112at-1m2......ATTI1,T2将右端第二个行列式中第n行和第n列提出公因子,后,再用-r,乘第n行加到第i行上去(1≤≤n-1),则D,=>D-1--,用递推公式并注意到D2=>2-(+),则有D-1.12计算n-21234n-1n..3n- 2134...n-1n25.1214n-1nD,±22n-534n-1-n1234n-22n-3.n123n-22m-1..n-1择从第行开始每行减去前一行,得解2[134..n-2n-1n0000100.00002120...Du000n-300000000n-2.n+300000.-n+2n-1按第一列展开后得到的行列式再按第一行展开,得:D,=(n-1)!计算1.13(a+h)(a+2h)(- 1)-[α +(n - 3)h] (- 1)n-2[a +(n-2)h) .(-1)-1[+(n-1)h1a0...0000a0.000aa+.....+-RP0000..a01000.**0aa解将行列式按第n列展开得00Q0a00000D, = (- 1)"+1 . (- 1)r-1[a + (n -1)h)+aD-1,000Ca000016
即D, = [a.+ (n - 1)h]a"-1 + aD, 1,从而Da-1 - [α +(n -2)h]a" 2 + aD,-2,D2=2a2+ah,n(n-1)所以D,=na"+ga-1h21.14计算32n-2..1-1n41x0...000...00-100aDa01000400001解从第二列开始,依次将前一列乘以工加到后,得一列,支+(n1)nz+(n-1)r+(n-2)(n)r110000-10.D, =-100000000-10n00-103(- 1)#-1-"-1-=(-1)"-1-1. (CZ1-07=0计算1.15h-100000...h-1000hr...0hr2h00hz-1..0Dn+1hz"-2hrr-3h2"-1hr-4hrh.-1hr"-1hz."-2hz"-3hr2ha"hrh依次每行减去前解从最后一行开始,一行的倍,得h-10000...00.00rth-10000- 1.000r+hDa+1h(r+h)"00000...r+h-10000...00r+h17
1.16计算1101111.10ai+a2.+ai+a3ai+an-2a1 +a-1ai+an01a2+ aja2+Q3a2+an-2a2+an-1az+anDa+i =01an-2 + a.-1an-2 + 41au-2+a2Qn-2+a3am-2+n10an-1+uan-1+a2an-j+asan-1 + an-2Qw-1 + a,10an+atun+a2an+asan + an-2an+an-1解将D+1中第i行的0写成-a:+a(i≠1),从而101+01+01 + 01+01+01 + 0..1...ai+Qtu1+a2ar+asG1 + 0g-2ar+ana1+an-11..aztat-a2 + 02a2+az02 + 4g-2Q2 + μa-)a2+anDa-1=an-2 + a31+a-2an~2+an-1an-z+a,an-2+a1an-2+a2an=21...au-1 +a2an-I + asan-l+alQn=1 +ag-2an-1 +un-14-1+an1",a + a1a,+a2a+a3an +aa-1u+a.an +an-21011.1111..-araiaiaraiar1...a2a2a2a2a2a21an-2an-2an~2a#-2ag-2an-21..an-1an-1a.-1an-1-an-1an-11...a,ananananan10100000.1I2010.000-a10001-202202...a200001-2an-22an-2.1000...0-2an-12aa-1/1000.00-2al10...0002a10001-2a22a2.= A..0001...-2ag-22a-20001...-2an-120m-11000.02an列不动,从最后一列得出第三个行列式,第三个行(第二个行列式第)一列依次减去前18
列式按第一行展开得△)将△,按最后一列展开,得:4, =- [(- 2an)An-1 + (- 1)2n-1 - 2an-1 · (- 1)n-1+1 . 2n-2 . a1 - a2--an-2]=-[(- 1)n-1 . 2"-1 . aia2"*an-2an-1 -2a,n-1]=- [(- 1)n"1 . 2"-1 . a1a2*-an-2an-1 - 2an[(- 1)n-2 . 2"-2a1*"-an-2 - 2an-14,-2]]-= -[(- 1)"-1 . 2"-lala2""an-1 +(- 1)"-1 - 2n-lal*an-2an + 4an-1a,A,-2]=- [(-1)"-1.2"-lai"*an-1 +(-1)"-1, 2"-la*"-an-2a, +*** + (- 1)"-12"-la2*"a,]/1+1+...+1=(-1)".2"-1a1a2"ana2a(1+1+...所以D.+1 = (-1)" . 2"-la1a2"..Cla121.17计算a2Q*-11...aa"1Q#-2aa"x11二,1元:1二-1α"~31221322...aDn+1 =1aIn-11Tn-12Tn-131.tnnTa1tn3tn2解从最后一列开始依次减去前一列的α倍100000001- af11.wi00.1 -ax22x21222-021D.+1 01Tn-1ara.r.ar.-121Xa2an1Xn3aTn2aranal-ar.-1Cnn-ari).1.183计算0r02y7D02yI0Ty解将第一列与其余各列相加知D可被++除尽.由第一列加上第二列并减去第三和第四列知D可被y+z-除尽,第一列加第三列减去第二、四列知D可被+除尽,第一列加上第四列减去第二、三列知D可被+一除尽。所有这些因子互质,即D可被它们的积(+)())(-)除尽该积中的系数为-1,而D含2的系数是1,于是19
D=-y+z)(y+z-a)(r-y+z)(rty-z)r1.19计算2314..n1n.0000-110..00-1010000-1D.=.400000...10000..-1r解从第二列开始,依次将前一列乘以加到后一列,得82+r3+2x+4+33+22+31ixJ2e2-0000010..000000-1Da00-10000...IEV0000-100V000000-1a-1)+i(- 1)#-1Zia(-13R-11.20计算ai+Ta2a3+..an-!an000.xi32000- T23D,6000.n-1000.an-1Ir解将D,按最后一列展开,得D, = xn - Dn-1 + (- 1)n+1 , an(- r1)(- r2).(- zn-1)=,D-1+Z122"n-1an从而Da-1=n-1·D-2+112""1-20n-1,D,-2=2n-2·Dn-3+X142*"3n-3an-2[an+ia2D2=2a1+xix2+xia21112所以D,=ria2***n-1an+ir2"+r2ra1+Tn-2ran-1++rr.20