设集合A={x|x^2-3x+2=0},B={x|x^2+2(a+1)x+(a^2-5)=0}.若U=R,A∩CuB=A,求实数a的取值范围.解析里给了若B≠∅则a≥-3此时1∉B且2∉B请问1∉B且2∉B怎么得出来的啊?
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![设集合A={x|x^2-3x+2=0},B={x|x^2+2(a+1)x+(a^2-5)=0}.若U=R,A∩CuB=A,求实数a的取值范围.解析里给了若B≠∅则a≥-3此时1∉B且2∉B请问1∉B且2∉B怎么得出来的啊?](/uploads/image/z/3942808-16-8.jpg?t=%E8%AE%BE%E9%9B%86%E5%90%88A%3D%EF%BD%9Bx%7Cx%5E2-3x%2B2%3D0%EF%BD%9D%2CB%3D%EF%BD%9Bx%7Cx%5E2%2B2%28a%2B1%29x%2B%28a%5E2-5%29%3D0%EF%BD%9D.%E8%8B%A5U%3DR%2CA%E2%88%A9CuB%3DA%2C%E6%B1%82%E5%AE%9E%E6%95%B0a%E7%9A%84%E5%8F%96%E5%80%BC%E8%8C%83%E5%9B%B4.%E8%A7%A3%E6%9E%90%E9%87%8C%E7%BB%99%E4%BA%86%E8%8B%A5B%E2%89%A0%26%238709%3B%E5%88%99a%E2%89%A5-3%E6%AD%A4%E6%97%B61%26%238713%3BB%E4%B8%942%26%238713%3BB%E8%AF%B7%E9%97%AE1%26%238713%3BB%E4%B8%942%26%238713%3BB%E6%80%8E%E4%B9%88%E5%BE%97%E5%87%BA%E6%9D%A5%E7%9A%84%E5%95%8A%3F)
设集合A={x|x^2-3x+2=0},B={x|x^2+2(a+1)x+(a^2-5)=0}.若U=R,A∩CuB=A,求实数a的取值范围.解析里给了若B≠∅则a≥-3此时1∉B且2∉B请问1∉B且2∉B怎么得出来的啊?
设集合A={x|x^2-3x+2=0},B={x|x^2+2(a+1)x+(a^2-5)=0}.若U=R,A∩CuB=A,求实数a的取值范围.
解析里给了若B≠∅
则a≥-3
此时1∉B且2∉B
请问1∉B且2∉B怎么得出来的啊?
设集合A={x|x^2-3x+2=0},B={x|x^2+2(a+1)x+(a^2-5)=0}.若U=R,A∩CuB=A,求实数a的取值范围.解析里给了若B≠∅则a≥-3此时1∉B且2∉B请问1∉B且2∉B怎么得出来的啊?
A={1,2}.
A∩CuB=A ,则CuB是A的子集,则B中不能包含A的元素,所以1∉B且2∉B
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