等差数列的前项和,则的最小值是 .
如图,已知U={1,2,3,4,5,6,7,8,9,10},集合A={2,3,4,5,6,8},B={1,3,4,5,7},C={2,4,5,7,8,9},用列举法写出图中阴影部分表示的集合为________.
设集合A={5,log2(a+3)},集合B={a,b}.若A∩B={2},则A∪B=________.
若全集U={1,2,3,4,5,6},M={2,3},N={1,4},则(∁UM)∩(∁UN)=________.
已知A={1,2,3},B={x∈R|x2-ax+1=0,a∈A},则A∩B=B时,a=________.
设集合U={1,2,3,4,5},A={1,2,3},B={2,3,4},则∁U(A∩B)=________.