|a b c d|D4= |c b d a| 则A14 + A24 + A34 + A44 = ()|d b c a||
|a b c d|D4= |c b d a| 则A14 + A24 + A34 + A44 = ()|d b c a||
D4 = a b c dc b d ad b c aa b d c则A14+A24+A34+A44 = 行列式a b c
( )-(c-d)=(a-c)-(-b+d)
a b c d* d_________=d c b a
实数a,b,c,d满足d>c;a+b=c+d;a+d
已知a:b=c:d,求证(a+c):(a-c)=(b+d):(b-d)
a>b>c>d>0.a/b=c/d怎么证明a+d>c+b
[a,b)×[c,d
a,b ,c ,d
若a/b=c/d,则(a-b)/b=(c-d)/d 请证明
D = b+c c+d a+b
求证(b,c,d)a+(c,a,d)b+(a,b,d)c+(b,a,c)d=0 a,b,c,d皆为向量>