Tham Khảo:

Every year, on January 13, Lim festival is held in Tien Du, Bac Ninh. While the festival is going on, there's a lot of activity. Like other festivals, the Lim festival is divided into ceremonies and festivals. The ceremony is organized with traditional rituals such as worshiping and rituals.

refer

Every year, on January 13, Lim festival is held in Tien Du, Bac Ninh. While the festival is going on, there's a lot of activity. Like other festivals, the Lim festival is divided into ceremonies and festivals. The ceremony is organized with traditional rituals such as worshiping and rituals.

Tham khảo

Every year, on January 13, Lim festival is held in Tien Du, Bac Ninh. While the festival is going on, there's a lot of activity. Like other festivals, the Lim festival is divided into ceremonies and festivals. The ceremony is organized with traditional rituals such as worshiping and rituals.

ta có \(\left(x-1\right)\left(3-x\right)\le\left(\frac{x-1+3-x}{2}\right)^2=1\le\left|y-2\right|+1\)

Dấu bằng xart ra khi:

\(\hept{\begin{cases}x-1=3-x\\y-2=0\end{cases}}\Leftrightarrow\hept{\begin{cases}x=2\\y=2\end{cases}}\)Vậy phương trình có nghiệm duy nhất (2,2)

x=3-1 

y=0+2

\(B=\left|x+1\right|+\left|x-4\right|+\left|2x-5\right|\ge\left|2x-3\right|+\left|2x-5\right|=\left|2x-3\right|+\left|5-2x\right|\)

\(\ge\left|2x-3+5-2x\right|=\left|2\right|=2\)

Dấu ''='' xảy ra khi \(\left(x+1\right)\left(4-x\right)\ge0;\left(2x-3\right)\left(5-2x\right)\ge0\)

\(-1\le x\le4;\frac{3}{2}\le x\le\frac{5}{2}\Rightarrow-1\le x\le4\)

Vậy GTNN của B bằng 2 tại -1 =< x =< 4 

1.wait

2.would miss

3.would have helped

4.had used

5.would be

6.will play

7.grew

8.would see

9.didn't have to do

10.had stayed up

ʂεμɭ❦

\(a;\left(\cos a-\sin a\right)\left(cosa+sina\right)=cos^2a-sin^2a=1-sin^2a-sin^2a=1-2sin^2a\)

\(b;VP=\left(2cosa-1\right)\left(2cosa+1\right)=4cos^2a-1=4\left(1-sin^2a\right)-1=3-4sin^2a=VT\)

e;\(\dfrac{1}{1+tana}+\dfrac{1}{1+cota}=1\Leftrightarrow cota+tana+2=\left(cota+1\right)\left(tana+1\right)\Leftrightarrow cota+tana+2=cota.tana+cota+tana+1\Leftrightarrow cota+tana+2=1+cota+tana+1\Leftrightarrow0=0\left(đúng\right)\Rightarrow VT=VP\)

\(d;sin^3a+cos^3a=\left(sina+cosa\right)\left(sin^2a-sina.cosa+cos^2a\right)=\left(sina+cosa\right)\left(1-sina.cosa\right)\left(đpcm\right)\left(hđt:a^3+b^3=\left(a+b\right)\left(a^2-ab+b^2\right)\right)\)

\(c;sin^2a.cosa+sina.cos^2a=\left(sina.cosa\right)\left(sin^2+cos^2\right)=sina.cosa\)

\(f;;tana+\dfrac{cosa}{1+sina}=\dfrac{sina}{cosa}+\dfrac{cosa}{1+sina}=\dfrac{sina+sin^2a+cos^2a}{cosa\left(1+sina\right)}=\dfrac{1+sina}{cosa\left(1+sina\right)}=\dfrac{1}{cosa}\)

\(g;1+cot^2a=\dfrac{1}{sin^2a}=\dfrac{1}{1-cos^2a}=\dfrac{1}{\left(1-cosa\right)\left(1+cosa\right)}\left(đpcm\right)\)

\(h;\dfrac{1+cosa}{1-cosa}-\dfrac{1-cosa}{1+cosa}=\dfrac{\left(cosa+1\right)^2-\left(cosa-1\right)^2}{1-cosa^2}=\dfrac{\left(cosa+1-cosa+1\right)\left(cosa+1+cosa-1\right)}{1-cos^2a}=\dfrac{4cosa}{sin^2a}\left(đpcm\right)\)

\(k;\dfrac{1+cosa}{sina}-\dfrac{sina}{1+cosa}=\dfrac{\left(cosa+1\right)^2-sin^2a}{sina\left(1+cosa\right)}=\dfrac{cos^2a+2cosa+1-sin^2a}{sina\left(1+cosa\right)}=\dfrac{2cos^2a+2cosa}{sina\left(1+cosa\right)}=\dfrac{2cosa\left(1+cosa\right)}{sina\left(1+cosa\right)}=\dfrac{2cosa}{sina}=2cota\left(đpcm\right)\)

\(m;;;\Leftrightarrow sin^3a=cosa\left(1+cosa\right)\left(tana-sina\right)=\left(cosa+cos^2a\right)\left(tana-sina\right)\Leftrightarrow sin^3a=\left(cosa+cos^2a\right)\left(\dfrac{sina}{cosa}-sina\right)=sina-sina.cosa+cosa.sina-cos^2a.sina\Leftrightarrow sin^3a=sina-cos^2a.sina\Leftrightarrow sin^3a-sina\left(1-cos^2a\right)=0\Leftrightarrow sin^3a-sina.sin^2a=0\Leftrightarrow0=0\left(đúng\right)\Rightarrowđpcm\)

\(n_{H_2}=\dfrac{8,96}{22,4}=0,4mol\\ n_{Al}=a;n_{Mg}=b\\ 2Al+6HCl\rightarrow2AlCl_3+3H_2\\ Mg+2HCl\rightarrow MgCl_2+H_2\\ \Rightarrow\left\{{}\begin{matrix}1,5a+b=0,4\\27a+24b=7,8\end{matrix}\right.\\ \Rightarrow a=0,2;b=0,1\\ \%m_{Al}=\dfrac{0,2.27}{7,8}\cdot100=69,23\%\\ \%m_{Mg}=100-69,23=30,77\%\)

Chữ khó nhìn quá bạn!

1, I suggest collecting boys

2, How about going to the beach

3, Because she was very tired, she went to bed

Khoa should use more efficient build

stopping using plastic bags

well

sings very sweetly

dances wonderfully