已知全集U=R,集合CUA={x|log2[(x-1)(x-7)+9]>2},B={x|(x-5)/(x-3)>2},则A和B的交集等于多少?

来源:学生作业帮助网 编辑:作业帮 时间:2024/05/02 10:43:54
已知全集U=R,集合CUA={x|log2[(x-1)(x-7)+9]>2},B={x|(x-5)/(x-3)>2},则A和B的交集等于多少?

已知全集U=R,集合CUA={x|log2[(x-1)(x-7)+9]>2},B={x|(x-5)/(x-3)>2},则A和B的交集等于多少?
已知全集U=R,集合CUA={x|log2[(x-1)(x-7)+9]>2},B={x|(x-5)/(x-3)>2},则A和B的交集等于多少?

已知全集U=R,集合CUA={x|log2[(x-1)(x-7)+9]>2},B={x|(x-5)/(x-3)>2},则A和B的交集等于多少?
log2[(x-1)(x-7)+9]>2
log2[(x-1)(x-7)+9]>log2(4)
(x-1)(x-7)+9>4
x²-8x+12>0
(x-2)(x-6)>0
x<2或x>6
CUA={x|x<2或x>6}
所以,A={x|2≦x≦6}
(x-5)/(x-3)>2
(x-5)/(x-3)-2>0
(x-5)/(x-3)-(2x-6)/(x-3)>0
(-x+1)/(x-3)>0
(-x+1)(x-3)>0
(x-1)(x-3)<0
1所以,B={x|1所以,A交B={x|2≦x<3}
祝你开心!希望能帮到你,如果不懂,请追问,祝学习进步!O(∩_∩)O