I'm going to visit Mui Ne this summer.

I'm going to visit Mui Ne this summer

use

is jane watching

doesn't go

is ating

do you study

am not listening- am playing

is raining- rains

are reading

am often playing=>often plays

is wanting=>wants

doesn't =>don't

have=>are having

skip=>skipping

is having=>has

cook =>am cooking

IV,

1. use

2. Is Jane watching...?

3. doesn't go

4. is eating

5. Do you sutdy...?

6. amn't listening... am playing

7. is going to rain... rains

8. are reading

V,

1. playing=> play

2. is wanting=> want

3. doesn't=> don't

4. have=> are having

5. skip=> skipping

6. is having=> has

7. cook=> am cooking

help j?/

ảnh bị lỗi nhé

c.

ĐKXĐ: \(sinx\ne0\Rightarrow x\ne k\pi\)

\(1-\dfrac{\sqrt{3}cosx}{sinx}-4cosx=0\)

\(\Rightarrow sinx-\sqrt{3}cosx-4sinx.cosx=0\)

\(\Leftrightarrow sinx-\sqrt{3}cosx=2sin2x\)

\(\Leftrightarrow\dfrac{1}{2}sinx-\dfrac{\sqrt{3}}{2}cosx=sin2x\)

\(\Leftrightarrow sin2x=sin\left(x-\dfrac{\pi}{3}\right)\)

\(\Leftrightarrow\left[{}\begin{matrix}2x=x-\dfrac{\pi}{3}+k2\pi\\2x=\dfrac{4\pi}{3}-x+k2\pi\end{matrix}\right.\)

\(\Leftrightarrow\left[{}\begin{matrix}x=-\dfrac{\pi}{3}+k2\pi\\x=\dfrac{4\pi}{9}+\dfrac{k2\pi}{3}\end{matrix}\right.\)

a.

\(\Leftrightarrow3sin3x-4sin^34x-\sqrt{3}cos9x=2sin2x\)

\(\Leftrightarrow sin9x-\sqrt{3}cos9x=2sin2x\)

\(\Leftrightarrow\dfrac{1}{2}sin9x-\dfrac{\sqrt{3}}{2}cos9x=sin2x\)

\(\Leftrightarrow sin\left(9x-\dfrac{\pi}{3}\right)=sin2x\)

\(\Leftrightarrow\left[{}\begin{matrix}9x-\dfrac{\pi}{3}=2x+k2\pi\\9x-\dfrac{\pi}{3}=\pi-2x+k2\pi\end{matrix}\right.\)

\(\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{\pi}{21}+\dfrac{k2\pi}{7}\\x=\dfrac{4\pi}{33}+\dfrac{k2\pi}{11}\end{matrix}\right.\)

b.

\(\Leftrightarrow\sqrt{3}cosx+sin3x-sinx-sin3x=\sqrt{2}\)

\(\Leftrightarrow\sqrt{3}cosx-sinx=\sqrt{2}\)

\(\Leftrightarrow\dfrac{\sqrt{3}}{2}cosx-\dfrac{1}{2}sinx=\dfrac{\sqrt{2}}{2}\)

\(\Leftrightarrow cos\left(x+\dfrac{\pi}{6}\right)=cos\left(\dfrac{\pi}{4}\right)\)

\(\Leftrightarrow\left[{}\begin{matrix}x+\dfrac{\pi}{6}=\dfrac{\pi}{4}+k2\pi\\x+\dfrac{\pi}{6}=-\dfrac{\pi}{4}+k2\pi\end{matrix}\right.\)

\(\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{\pi}{12}+k2\pi\\x=-\dfrac{5\pi}{12}+k2\pi\end{matrix}\right.\)

Help mik đi mik tick cho

\(\dfrac{2}{7}=\dfrac{10}{35}=\dfrac{12}{42}=\dfrac{16}{56}\)

2/7=10/35=12/42=16/56

đề :)?

2.A

3.A