来自谈大龙的问题
设集合A={-1,1,4},B={a+2,a2+3},则A∩B={4}时,则实数a=______.
设集合A={-1,1,4},B={a+2,a2+3},则A∩B={4}时,则实数a=______.
1回答
2020-02-08 20:28
设集合A={-1,1,4},B={a+2,a2+3},则A∩B={4}时,则实数a=______.
设集合A={-1,1,4},B={a+2,a2+3},则A∩B={4}时,则实数a=______.
∵集合A={-1,1,4},B={a+2,a2+3},A∩B={4}时,
∴a+2=4,或a2+3=4.
当a+2=4 时,a=2,满足A∩B={4};
当a2+3=4,则a=±1;
若a=-1,B={1,4},不满足A∩B={4};
若a=1,B={3,4},满足A∩B={4}.
∴实数a=2,或a=1,
故答案为:2或1.