In Vietnamese have many drink but i most is water. It don't have color, taste, smell but it very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very ery very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very ery very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very ery very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very ery very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very ery very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very ery very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very ery very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very ery very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very ery very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very ery very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very ery very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very ery very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very good.

Chúc bạn học tốt !  👍👍👍👍👍👍👍👍👍👍👍👍👍

được không bạn

• lacnguyet
• 25/03/2020

Tác dụng: Nhấn mạnh lí do vì sao mà nhân vật "tôi" lại " làm điệu dún dẩy các khoeo chân, rung lên rung xuống hai chiếc râu"

\(\frac{1}{x}-\frac{1}{y}=\frac{1}{x}.\frac{1}{y}\)

\(=>\frac{y-x}{xy}=\frac{1}{xy}\)

\(=>xy^2-x^2y=xy\)

\(=>xy^2-x^2y-xy=0\)

\(=>x.\left(y^2-xy-y\right)=0\)

\(=>\orbr{\begin{cases}x=0\\y^2-xy-y=0\end{cases}}\)

Ta thấy \(y^2-xy-y=0\)

\(=>y.\left(y-x-y\right)=0\)

\(=>\orbr{\begin{cases}y=0\left(2\right)\\y-y=0\end{cases}}\)

Từ 1 và 2 => x = y = 0

\(\frac{1}{x}-\frac{1}{y}=\frac{1}{x}.\frac{1}{y}\)

\(\Rightarrow\frac{y-x}{xy}=\frac{1}{xy}\)

\(\Rightarrow y-x=1\)

Vậy x,y có dạng \(\hept{\begin{cases}x=y-1\\y=x+1\end{cases}}\)với \(y\ne1;x\ne-1;x\ne0;y\ne0\)

Xét khoảng \(x< 1\)

PTTT: \(\left(1-x\right)-2\left(2-x\right)=0\)

\(\Leftrightarrow1-x-4+2x=0\Leftrightarrow x=5\left(L\right)\)

Xét khoảng \(1\le x\le2\)

PTTT: \(\left(x-1\right)-2\left(2-x\right)=0\)

\(\Leftrightarrow x-1-4+2x=0\)

\(\Leftrightarrow3x=5\Leftrightarrow x=\frac{5}{3}\left(tm\right)\)

Xét khoảng x > 2

PTTT: \(\left(x-1\right)-2\left(x-2\right)=0\)

\(\Leftrightarrow x-1-2x+4=0\)

\(\Leftrightarrow-x=-3\Leftrightarrow x=3\)

Vậy tập nghiệm \(S=\left\{3;\frac{5}{3}\right\}\)

\(|x-1|-2.|x-2|=0\)

\(Th1:|x-1|-2=0\)

\(\Leftrightarrow|x-1|=2\)

\(\Leftrightarrow\orbr{\begin{cases}x-1=2\\x-1=-2\end{cases}\Leftrightarrow\orbr{\begin{cases}x=3\\x=-1\end{cases}}}\)

\(Th2:|x-2|=0\Leftrightarrow x-2=0\Leftrightarrow x=2\)