设R={(1,1),(2,1),(3,2),(4,3)},求幂R^n,n=2,3,4...
设R={(1,1),(2,1),(3,2),(4,3)},求幂R^n,n=2,3,4...
C(0,n)+2C(1,n)+3C(2,n)+...+(r+1)C(r,n)+...+(n+1)C(n,n)=___(n
n=3r. 又有[(3r)(3r-1)(3r-2)……(2r+1)]/(r!)2^r=60 怎么解得?
设A={1,2,3},给定A上二元关系R={,,},求r(R),s(R)和t(R).
算组合数、、已知2n=3r C(n.r)=84 求n
设A为n阶(n≥2)方阵,证明r(A*)= n ,r(A)=n r(A*)= 1,r(A)=n-1 r(A*)= 0,r
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)
证明C(r+1,n)+ 2C(r,n)+C(r-1,n) = C(r+1,n+2)
设全集为R,集合M={x|2x>x+3},N={x|-1
设集合M={y|y=x²-3,x∈R},N={y|y=-2x²+1,x∈R},求M∩N,M∪N
设全集U=R,(1)M={x||2x+1|>1},N={x|3+x/(1-x)大于等于0},求M∪N
离散数学:设A=(1,2,3)R为AxA上的等价关系,R={,,}求r(R),s(R),t(R)