设集合A={x|x²-3x+2=0}B={x|x²+2(a+1)x+(a²-5)=01若A∩B={2},求实数a的值2若A∪B=A,求实数a的取值范围
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![设集合A={x|x²-3x+2=0}B={x|x²+2(a+1)x+(a²-5)=01若A∩B={2},求实数a的值2若A∪B=A,求实数a的取值范围](/uploads/image/z/1806080-32-0.jpg?t=%E8%AE%BE%E9%9B%86%E5%90%88A%3D%7Bx%7Cx%26%23178%3B-3x%2B2%3D0%7DB%3D%7Bx%7Cx%26%23178%3B%2B2%28a%2B1%29x%2B%28a%26sup2%3B-5%29%3D01%E8%8B%A5A%E2%88%A9B%3D%7B2%7D%EF%BC%8C%E6%B1%82%E5%AE%9E%E6%95%B0a%E7%9A%84%E5%80%BC2%E8%8B%A5A%E2%88%AAB%3DA%EF%BC%8C%E6%B1%82%E5%AE%9E%E6%95%B0a%E7%9A%84%E5%8F%96%E5%80%BC%E8%8C%83%E5%9B%B4)
设集合A={x|x²-3x+2=0}B={x|x²+2(a+1)x+(a²-5)=01若A∩B={2},求实数a的值2若A∪B=A,求实数a的取值范围
设集合A={x|x²-3x+2=0}B={x|x²+2(a+1)x+(a²-5)=0
1若A∩B={2},求实数a的值
2若A∪B=A,求实数a的取值范围
设集合A={x|x²-3x+2=0}B={x|x²+2(a+1)x+(a²-5)=01若A∩B={2},求实数a的值2若A∪B=A,求实数a的取值范围
A={x|x²-3x+2=0}={1,2},
B={x|x²+2(a+1)x+(a²-5)=0.
1.A∩B={2},把x=2代入B的方程得
4+4(a+1)+a^2-5=0,
a^2+4a+3=0,
a=-1,或-3.
a=-1时B={x|x^2-4=0)={土2},满足题设;
a=-3时B={x|x^2-4x+4=0)={2},满足题设.
2.A∪B=AB是A的子集,
1)B为空集,△/4=(a+1)^2-(a^2-5)=2a+6
1.你题目出错了;
2.也就是A是B的子集,要考虑3种情况
(1)B=空集;
(2)B是单元素集{1}或者是{2}
(3)B=A
去算算吧,做为高一的学生还是自己多动手的好,答案是a<-21/8
A={1,2},
1,a=-1,-3.
2,a={±1,a≤-3