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. 设集合 A={a1,a2,a3,a4}A=\left\{a_{1}, a_{2}, a_{3}, a_{4}\right\} ,若集合 AA 中所有三个元素的子集中的三个元素之和组...
Mar 8, 2024
. 设集合 A={a1,a2,a3,a4}A=\left\{a_{1}, a_{2}, a_{3}, a_{4}\right\} ,若集合 AA 中所有三个元素的子集中的三个元素之和组成的集合为 B={2,3,4,6}B=\{2,3,4,6\} ,则集合 A=A=
Solution by Steps
step 1
To find the set A A , we need to solve the system of equations given by the sums of the subsets of three elements each
step 2
The system of equations is: a1+a2+a3=2 a1 + a2 + a3 = 2 , a1+a2+a4=3 a1 + a2 + a4 = 3 , a1+a3+a4=4 a1 + a3 + a4 = 4 , a2+a3+a4=6 a2 + a3 + a4 = 6
step 3
Solving this system of equations, we find that a1=1 a1 = -1 , a2=1 a2 = 1 , a3=2 a3 = 2 , and a4=3 a4 = 3
step 4
Therefore, the set A A is {1,1,2,3} \{-1, 1, 2, 3\}
Answer
A={1,1,2,3} A = \{-1, 1, 2, 3\}
Key Concept
Solving a system of linear equations
Explanation
The solution to the system of equations represents the elements of set A A such that the sums of all possible three-element subsets match the elements of set B B .
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