设A,B,C,D是任意集合,求证:(A∩B)x(C∩D)=(AxC)∩(BxD)
设A,B,C,D是任意集合,求证:(A∩B)x(C∩D)=(AxC)∩(BxD)
设A,B,C,D是任意的集合.证明(A交B)×(C交D)=(A×C)交(B×D)
设集合A={a,b,c,d,e},集合B={c,d,f,g},求A∩B,A∪B.
设A,B,C是三个任意集合,证明:A×(B∪C)=(AB)∪(A×C),A×(B∩ C)=(AB)∩ (A×C)
设A,B,C是三个任意集合,试证A∩(B∪C)=(A∩B)∪(A∩C)
集合A=(a, b, c),集合B=(c ,d ,e ,f),则A∩B=?
(A-B)×C=(A×C)-(B×C)是否对任意集合A,B,C,D均成立?
设a,b,c,d为正数,求证(a+c/a+b)+(b+d/b+c)+(c+a/c+d)+(d+b/d+a)≥4
已知a:b=c:d,求证(a+c):(a-c)=(b+d):(b-d)
A,B,C,D均为集合,证明(A-B)-C=(A-C)-(B-C)和(A*C)∩(B*D)=(A∩B)*(C∩D)
设全集U={a,b,c,d,e,f},A={a,c,e,f},B={b,c,d,e},分别求集合Cu(A∩B)和CuA∪
设a,b,c满足ab+bc+cd+da=1,求证:a^3/(b+c+d)+b^3/(a+c+d)+c^3/(a+b+d)