共50条信息
设集合\(A=\left\{ x\left| x\leqslant a \right. \right\}\),\(B=\left( -\infty ,2 \right)\),若\(A\subseteq B\),则实数\(a\)的取值范围是 .
已知集合\(A=\left\{ \left. x\left| \left. x-2\leqslant 0,x∈N \right. \right. \right. \right\}\),\(B=\left\{ \left. x\left| \left. \sqrt{x}\leqslant 2,x∈Z \right. \right. \right. \right\}\),则满足条件\(A⊆C⊆B\)的集合\(C\)的个数为\((\) \()\)
设集合\(A=\{x|y=\lg (-x^{2}+x+2)\}\),\(B=\{x|x-a > 0\}\),若\(A⊆B\),则实数\(a\)的取值范围是\((\) \()\)
已知集合\(A{=}\{ x{|}x^{2}{-}x{-}2{ < }0\}{,}B{=}\{ y{|}y{=}\sin x{,}x{∈}R\}\),则\(({ }{\ \ \ \ }{ })\)
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