Giúp mình phần E với
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b: Xét tứ giác ADME có
\(\widehat{ADM}=\widehat{AEM}=\widehat{DAE}=90^0\)
Do đó: ADME là hình chữ nhật
c/ \(y=\sqrt[3]{\frac{3x+1}{x^2-1}}\)
Tập xác định \(D=R\backslash\left\{\pm1\right\}\)
d/ \(y=\frac{\sqrt{x^2-4x+4}+\sqrt{x^2-6x+9}}{\sqrt{x^2-x+1}}=\frac{\sqrt{\left(x-2\right)^2}+\sqrt{\left(x-3\right)^2}}{\sqrt{x^2-x+\frac{1}{4}+\frac{3}{4}}}=\frac{\left|x-2\right|+\left|x-3\right|}{\sqrt{\left(x-\frac{1}{2}\right)^2+\frac{3}{4}}}\)
Suy ra tập xác định D = R
e/ \(y=\frac{1}{x^2+5x+6}=\frac{1}{\left(x+3\right)\left(x+2\right)}\) . Để y xác định thì \(\left(x+3\right)\left(x+2\right)\ne0\) => x khác -2 và -3
Suy ra tập xác định : \(D=R\backslash\left\{-2;-3\right\}\)
b/ \(y=\sqrt{x^2-2x+1}+\sqrt{x-3}+\sqrt{4-x}+1\)
\(=\sqrt{\left(x-1\right)^2}+\sqrt{x-3}+\sqrt{4-x}+1\)
\(=\left|x-1\right|+\sqrt{x-3}+\sqrt{4-x}+1\)
Để y xác định thì \(\begin{cases}x-3\ge0\\4-x\ge0\end{cases}\) \(\Rightarrow3\le x\le4\)
Vậy tập xác định là thuộc đoạn \(\left[3;4\right]\)
Bài 2:
Ta có: \(3n^3+10n^2-5⋮3n+1\)
\(\Leftrightarrow3n^3+n^2+9n^2+3n-3n-1-4⋮3n+1\)
\(\Leftrightarrow3n+1\in\left\{1;-1;2;-2;4;-4\right\}\)
\(\Leftrightarrow3n\in\left\{0;-3;3\right\}\)
hay \(n\in\left\{0;-1;1\right\}\)
A.2x + 1 < 100
2x < 100-1=99
x ≤ 98/2=49
Mà {x E N* | x ≤ 49 }
Nên tập hợp B có 49 phần tử
B.(49-1) x 49 :2= 1176
C. 1 +(32-1)x 1= 32
E = 2x2 + 3x + 8
= 2( x2 + 3/2x + 9/16 ) + 55/8
= 2( x + 3/4 )2 + 55/8 ≥ 55/8 ∀ x
Dấu "=" xảy ra khi x = -3/4
=> MinE = 55/8 <=> x = -3/4
refer
1. We are trying to introduce our handicraft products to foreign tourists in order that we promote our culture.
2. Although Bat Trang village is quite far from my place, I still want to go there with my friend this weekend
3. The development of traditional handicrafts in Vietnam has faced up to many challenges
4. He is going to take charge of his family business because his parents are very old
5. Most people in this village live on making traditional handicrafts.
1 We are trying to introduce our handicraft products to foreigner in order that we can promote our culture
2 Allthough BatTrang village is quite far from my place, I still want.......
3 The developement of traditional handicrafts in VN has faced up to many challenges
4 He is going to take charge of his family business because his parents are very old now
5 Most people in this village live on making traditional handicrafts