Cho 2 tập hợp:
\(A=\left\{x\in R,x+2>m\right\}\)
\(B=\left\{x\in R,x\le1\right\}\)
Tìm m để \(A\cup B\)
Cho \(A=\left\{x\in R|\left(x+1\right)^2+\left(x-1\right)^2=10\right\};B=\left\{x\in R|\left(x+1\right)^4+\left(x-1\right)^4=82\right\}\)Tìm tập X sao cho A\(\cup\)X=B.
Cho \(A=\left\{x\in R/\frac{1}{\left|x-2\right|}>2\right\}\);\(B=\left\{x\in R/\left|x-1\right|< 1\right\}\).Hãy tìm \(A\cup B,A\B\)
\(\frac{1}{\left|x-2\right|}>2\Rightarrow\left|x-2\right|< \frac{1}{2}\Rightarrow-\frac{1}{2}< x-2< \frac{1}{2}\)
\(\Rightarrow\frac{3}{2}< x< \frac{5}{2}\)
\(\Rightarrow A=\left(\frac{3}{2};\frac{5}{2}\right)\)
\(\left|x-1\right|< 1\Rightarrow-1< x-1< 1\Rightarrow0< x< 2\)
\(\Rightarrow B=\left(0;2\right)\)
\(\Rightarrow A\cup B=\left(0;\frac{5}{2}\right)\)
\(A\backslash B=[2;\frac{5}{2})\)
Xác định các tập: \(A\cup B,A\cap B;A\backslash B;B\backslash A\)
a, \(A=\left\{x\in R|-3\le x\le5\right\};B==\left\{x\in R|\left|x\right|< 4\right\}\)
b, \(A=\left[1;5\right];B=\left(-3;2\right)\cup\left(3;7\right)\)
c, \(A=\left\{x\in R|\dfrac{1}{\left|x-1\right|}\ge2\right\};B=\left\{x\in R|\left|x-2\right|\le1\right\}\)
d, \(A=\left[0;2\right]\cup\left(4;6\right);B=(-5;0]\cup\left(3;5\right)\)
a, \(A\cup B=(-4;5]\)
\(A\cap B=[-3;4)\)
\(A\backslash B=\left[4;5\right]\)
\(B\backslash A=\left(-4;-3\right)\)
b, \(A\cup B=\left(-3;7\right)\)
\(A\cap B=[1;2)\cup(3;5]\)
\(A\backslash B=\left[2;3\right]\)
\(B\backslash A=\left(-3;1\right)\cup\left(5;7\right)\)
c, \(A\cup B=\left[\dfrac{1}{2};3\right]\)
\(A\cap B=\left[1;\dfrac{3}{2}\right]\)
\(A\backslash B=[\dfrac{1}{2};1)\)
\(B\backslash A=(\dfrac{3}{2};3]\)
d, \(A\cup B=(-5;2]\cup(3;6]\)
\(A\cap B=\left\{0\right\}\cup[4;5)\)
\(A\backslash B=(0;2]\cup\left[-5;6\right]\)
\(B\backslash A=[-5;0)\cup\left(3;4\right)\)
Cho tập \(A=\left(-\infty,-1\right)\cup\left(2,+\infty\right)\\ B=\left[-3.1\right]\)
Tìm m để \(C\dfrac{A}{B}\subset C\) biết \(C=\left\{x\in R\left|\left|2x-1\right|\le m\right|\right\}\)
Cho \(E=\left\{x\in Z|\left|x\right|\le5\right\}\); \(A=\left\{x\in R|x^2+3x-4=0\right\}\);
\(B=\left\{x\in Z|(x-2)(x+1)(2x^2-x-3)=0\right\}\)
a) CM \(A\subset E\),\(B\subset E\)
b) Tìm \(E\backslash\left(A\cap B\right)\),\(E\backslash\left(A\cup B\right)\) rồi tìm quan hệ giữa hai tập hợp này.
\(E=\left\{-5;-4;-3;-2;-1;0;1;2;3;4;5\right\}\)
\(A=\left\{1;-4\right\}\)
\(B=\left\{2;-1\right\}\)
a) Với mọi x thuộc A đều thuộc E \(\Rightarrow A\subset E\)
Với mọi x thuộc B đều thuộc E \(\Rightarrow B\subset E\)
b) \(A\cap B=\varnothing\)
\(\Rightarrow E\backslash\left(A\cap B\right)=\left\{-5;-4;-3;-2;-1;0;1;2;3;4;5\right\}\)
\(A\cup B=\left\{-4;-1;1;2\right\}\)
\(\Rightarrow E\backslash\left(A\cup B\right)=\left\{-5;-3;-2;0;3;4;5\right\}\)
\(\Rightarrow E\backslash\left(A\cup B\right)\subset E\backslash\left(A\cap B\right)\)
M = \(\left(\frac{x}{x^2-4}+\frac{2}{2-x}+\frac{1}{x+2}\right)\div\left(x-2+\frac{10-x^2}{x+2}\right)\)
a) Tìm Tập xác định
b) Rút gọn M
c) Tìm M khi \(\left|x\right|\) = \(\frac{1}{2}\)
d) Tìm \(x\in Z\) để \(M\in Z\)
a: ĐKXĐ: \(x\notin\left\{2;-2\right\}\)
b: \(M=\left(\dfrac{x}{\left(x-2\right)\left(x+2\right)}-\dfrac{2}{x-2}+\dfrac{1}{x+2}\right):\dfrac{x^2-4+10-x^2}{x+2}\)
\(=\dfrac{x-2x-4+x-2}{\left(x-2\right)\left(x+2\right)}\cdot\dfrac{x+2}{6}\)
\(=\dfrac{-1}{x-2}\)
d: Để M nguyên thì \(x-2\in\left\{1;-1\right\}\)
hay \(x\in\left\{3;1\right\}\)
a, A = [ -2; 5)
B= ( - \(\infty\); 3 ]
C=(- \(\infty\) ; 4 )
3. Cho A=\(\left\{x^{ }\in R|\left(x^2-7x+6\right)\left(x^2-4\right)=0\right\}\)
B=\(\left\{x\in Z|-3< x< \sqrt{7}\right\}\)
Tìm A\(\cap\)B, A\(\cup\)B
Cho A =\(\left\{x\in R|\left|mx-3\right|=mx-3\right\}\) , B=\(\left\{x\in R|x^2-4=0\right\}\).Tìm m để B\A = B
\(\left|mx-3\right|=mx-3\Leftrightarrow mx-3\ge0\) \(\Rightarrow\left[{}\begin{matrix}x\ge\dfrac{3}{m}\left(m>0\right)\\x\le\dfrac{3}{m}\left(m< 0\right)\end{matrix}\right.\)
\(x^2-4=0\Rightarrow x=\pm2\Rightarrow B=\left\{-2;2\right\}\)
\(B\backslash A=B\Leftrightarrow A\cap B=\varnothing\)
\(\Rightarrow\left[{}\begin{matrix}\dfrac{3}{m}>2\left(m>0\right)\\\dfrac{3}{m}< -2\left(m< 0\right)\end{matrix}\right.\) \(\Rightarrow\left[{}\begin{matrix}0< m< \dfrac{3}{2}\\-\dfrac{3}{2}< m< 0\end{matrix}\right.\)