Giải bài 1 trang 16

Đề bài

Xác định A∩B,A∪B,A∖B,B∖A$A\cap B,A\cup B,A\setminus B,B\setminus A$ trong các trường hợp sau:

a) A={a;b;c;d},B={a;c;e}$A=\left\{a;b;c;d\right\},B=\left\{a;c;e\right\}$

b) A={x|x2−5x−6=0},B={x|x2=1}$A=\left\{x|x^2-5x-6=0\right\},B=\left\{x|x^2=1\right\}$

c) A={x∈N|x$A=\{x\in N|x$ là số lẻ, x<8$x<8$ , B={x∈N|x$B=\{x\in N|x$ là các ước của 12}

Lời giải chi tiết

a) A∩B={a;c},A∪B={a;b;c;d;e}$A\cap B=\left\{a;c\right\},A\cup B=\left\{a;b;c;d;e\right\}$

A∖B={b;d},B∖A={e}$A\setminus B=\left\{b;d\right\},B\setminus A=\left\{e\right\}$

b) Giải các phương trình ta có: A={−1;6},B={−1;1}$A=\left\{-1;6\right\},B=\left\{-1;1\right\}$A∩B={−1},A∪B={−1;1;6}$A\cap B=\left\{-1\right\},A\cup B=\left\{-1;1;6\right\}$

A∖B={6},B∖A={1}$A\setminus B=\left\{6\right\},B\setminus A=\left\{1\right\}$

c) Ta xác định được A={1;3;5;7},B={1;2;3;4;6;12}$A=\left\{1;3;5;7\right\},B=\left\{1;2;3;4;6;12\right\}$

A∩B={1;3},A∪B={1;2;3;4;5;6;7;12}$A\cap B=\left\{1;3\right\},A\cup B=\left\{1;2;3;4;5;6;7;12\right\}$

A∖B={5;7},B∖A={2;4;6;12}$A\setminus B=\left\{5;7\right\},B\setminus A=\left\{2;4;6;12\right\}$