共50条信息
设集合\(A=\{x|x^{2}-2x-3 < 0\}\),\(B=\{x|x > 0\}\),则\(A∪B=\) \((\) \()\)
设集合\(A=\left\{ \left. 5, \dfrac{b}{a},a-b \right. \right\}\),\(B=\{b,a+b,-1\}\),若\(A∩B=\{2,-1\}\),则\(A∪B=(\) \()\)
已知集合\(A=\{1,2,3\} \),\(B=\{x|(x+1)(x-2) < 0,x∈Z\}, \),则\(A∪B= (\) \()\)
已知集合 \(A=\)\(\{ \)\(x|-\)\(1\) \( < x < \)\(1\}\), \(B=\)\(\{ \)\(x|x < a\)\(\}\),若 \(A\)\(∪\) \(B=\)\(\{ \)\(x|x < \)\(1\}\),则 \(a\)的取值范围是 .
已知集合\(A={ }\!\!\{\!\!{ }x\in Z||{{x}^{2}}-4x| < 4\}\),\(B=\{y\in {{N}_{+}}|{{\left( \dfrac{1}{2} \right)}^{y}}\geqslant \dfrac{1}{8}\}\),记\({card}A\)为集合\(A\)的元素个数,则下列说法不正确的是\((\) \()\)
已知集合\(A=\{x|y=\lg (3-2x)\}\),\(B=\{x|x^{2}\leqslant 4\}\),则\(A∪B=(\) \()\)
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