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            • 1. 若{1,2}⊆A⊆{1,2,3,4,5},则集合A的个数是(  )
              A.8
              B.7
              C.4
              D.3
            • 2.

              已知集合\({{A}_{n}}=\{({{x}_{1}},{{x}_{2}},\cdots \cdots ,{{x}_{n}})|{{x}_{i}}\in \{-1,1\}(i=1,2,\cdots ,n){ }\!\!\}\!\!{ }\)\(x,y\in {{A}_{n}}\)\(x=({{x}_{1}},{{x}_{2}},\cdots ,{{x}_{n}})\)\(y=({{y}_{1}},{{y}_{2}},\cdots ,{{y}_{n}})\),其中\({{x}_{i}},{{y}_{i}}\in \{-1,1\}(i=1,2,\cdots ,n)\)

              定义\(x\odot y={{x}_{1}}{{y}_{1}}+{{x}_{2}}{{y}_{2}}+\cdots +{{x}_{n}}{{y}_{n}}.\)若\(x\odot y=0\),则称\(x\)与\(y\)正交.

              \((\)Ⅰ\()\)若\(x=(1,1,1,1)\),写出\({{A}_{4}}\)中与\(x\)正交的所有元素;

              \((\)Ⅱ\()\)令\(B=\{x\odot y|x,y\in {{A}_{n}}\}.\)若\(m\in B\),证明:\(m+n\)为偶数;

              \((\)Ⅲ\()\)若\(A\subseteq {{A}_{n}}\),且\(A\)中任意两个元素均正交,分别求出\(n=8,14\)时,\(A\)中最多可以有多少个元素.

            • 3.

              已知\(e\)为自然对数的底数,若对任意的\(x\in [\dfrac{1}{e},1]\),总存在唯一的\(y\in [-1,1]\),使得\(\ln x-x+1+a={{y}^{2}}{{e}^{y}}\)成立,则实数\(a\)的取值范围是 

              A.\((\dfrac{2}{e},+\infty )\)
              B.\((\dfrac{2}{e},e+\dfrac{1}{e})\)
              C.\([\dfrac{1}{e},e]\)
              D.\((\dfrac{2}{e},e]\)
            • 4.

              满足\(\left\{0,1,2\right\} \overset{⊂}{\neq } \)​\(A⊆\left\{0,1,2,3,4,5\right\} \)的集合\(A\)的个数是_______个。

            • 5.
              已知\(A=\{0,2,3,4,5,7\}\),\(B=\{1,2,3,4,6\}\),\(C=\{x|x∈A,\) \(\}\),则\(C\)的真子集个数为
              A.\(2\)
              B.\(3\)
              C.\(7\)
              D.\(8\)
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