Cho hai tập hợp A=(1;5];B=(2;7]. Tập hợp A\B là
Hãy suy nghĩ và trả lời câu hỏi trước khi xem đáp án
$A = (1; 5]$ là tập hợp các số thực lớn hơn 1 và nhỏ hơn hoặc bằng 5.
$B = (2; 7]$ là tập hợp các số thực lớn hơn 2 và nhỏ hơn hoặc bằng 7.
$A \backslash B$ sẽ chứa các phần tử của A mà không nằm trong B.
Vì $A = (1; 5]$ và $B = (2; 7]$, thì $A \cap B = (2; 5]$.
Vậy, $A \backslash B = A - (A \cap B) = (1; 5] - (2; 5] = (1; 2]$.
Do đó, đáp án là $(1; 2]$
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