Question

T​ìm A\(\cap\)B; A\(\cup\)B; A\B; B\A biết: a) A=[2;6] và B =[3;5]. b) A= {x​ \(\in\)Q\(|\)1\(\le\)x\(\le\) 4} và B={3;4;5}

Answer 1

Lời giải:

a)

\(A\cap B =\left \{ x\in\mathbb{R}| 3\leq x\leq 5 \right \}\)

\(A\cup B= \left \{ x\in\mathbb{R}| 2\leq x\leq 6 \right \}\)

\(A\setminus B =\left \{ x\in\mathbb{R}| 2\leq x< 3, 5< x\leq 6 \right \}\)

\(A\setminus B =\left \{ \oslash \right \}\)

b)

\(A\cap B =\left \{ 3;4 \right \}\)

\(A\cup B =\left \{x\in\mathbb{Q}|1\leq x\leq 4 \right \}\)

\(A\setminus B =\left \{x\in\mathbb{Q}|1\leq x<3, 3< x< 4 \right \}\)

\(B\setminus A =\left \{5 \right \}\)