3.[判断题]设A_(1),A_(2),...,A_(n)为n个事件,若对任意的i,j(1≤i,j≤n),均有P(A_(i)A_(j))=P(A_(i))P(A
设A_(1),A_(2),...,A_(n),...是事件列,若A_(n)subset A_(n+1),n=1,2,...,A=bigcap_(i=1)^inf
(3)设a_(n)>0(n=1,2,...),S_(n)=a_(1)+a_(2)+...+a_(n),则数列S_(n)有界是数列a_(n)收敛的A. 充分必要条
2、设级数sum_(n=1)^inftya_(n)收敛,lim_(ntoinfty)na_(n)=a.证明:sum_(n=1)^inftyn(a_(n)-a_(
4.设A=(a_(ij))为3阶矩阵,A_(ij)表示A中(i,j)元的代数余子式,若A的每行元素之和均为2,且|A|=2,则A_(11)+A_(21)+A_(
练习 (2021,1)设A=[a_(ij)]为三阶矩阵,A_(ij)为元素a_(ij)的代数余子式,若A的每行元素之和均为2,且|A|=3,则A_(11)+A_
若n阶行列式D_(n)=|a_(ij)|=k,则n阶行列式D=|-a_(ij)|=()A. $(-1)^{n}k$B. $k^{n}$C. kD. -k
& a_(1n) a_(21) & a_(22) & ... & a_(2n) vdots & vdots &
& a_(1n) a_(21) & a_(22) & ... & a_(2n) vdots & vdots &
4.设A_(2n-1)=(0,(1)/(n)),A_(2n)=(0,n),n=1,2,….求出集列(A_{n)}的上限集和下限集.4.设$A_{2n-1}=\l