beginresult =N*r/pre;
怎么证明R(AB)>=R(A)+R(B)-N
组合恒等式的证明:C(r,r)+C(r+1,r)+C(r+2,r)+…+C(n,r)=C(n+1,r+1) C(n,1)
r=m MOD n
证明C(r+1,n)+ 2C(r,n)+C(r-1,n) = C(r+1,n+2)
算组合数、、已知2n=3r C(n.r)=84 求n
证明对于n阶矩阵A,若R(A)=n,则R(A2)=n
设A为n阶矩阵,证明r(A^n)=r(A^(n+1))
AB=0,证明:r(a)+r(b)≤n
C(0,n)+2C(1,n)+3C(2,n)+...+(r+1)C(r,n)+...+(n+1)C(n,n)=___(n
英语翻译Pre-teenage R&B sensations in the early '90s,Immature we
英语翻译The pre-flash code should be different as well ,just a r
设A是m*n矩阵,且R(A)=r,则当r=m,r=n,m=n,r