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help với ạ
DT
Đỗ Thanh Hải
CTVVIP
29 tháng 6 2021
53 Are there 800 pupils in you school?
53 There are 6 children in your family
55 How much do a cack and an orange cost?
57 How much does a bottle of cooking oil cost
59 My father is going to Ha Noi by car
60 Nam's father has a white car
61 How much beef would you like
63 I go to school by bicycle everyday
65 Phong's sister is nhung
67 Trung is Mr Minh's son
68 Huyen goes to school on foot...
69Nam is Phuong's brother
help với ạ
help với ạ
KY
5 tháng 7 2021
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
MN
5 tháng 7 2021
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
NV
Nguyễn Việt Lâm
Giáo viên
14 tháng 9 2021
c.
ĐKXĐ: \(sinx\ne0\Rightarrow x\ne k\pi\)
\(1-\dfrac{\sqrt{3}cosx}{sinx}-4cosx=0\)
\(\Rightarrow sinx-\sqrt{3}cosx-4sinx.cosx=0\)
\(\Leftrightarrow sinx-\sqrt{3}cosx=2sin2x\)
\(\Leftrightarrow\dfrac{1}{2}sinx-\dfrac{\sqrt{3}}{2}cosx=sin2x\)
\(\Leftrightarrow sin2x=sin\left(x-\dfrac{\pi}{3}\right)\)
\(\Leftrightarrow\left[{}\begin{matrix}2x=x-\dfrac{\pi}{3}+k2\pi\\2x=\dfrac{4\pi}{3}-x+k2\pi\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}x=-\dfrac{\pi}{3}+k2\pi\\x=\dfrac{4\pi}{9}+\dfrac{k2\pi}{3}\end{matrix}\right.\)
NV
Nguyễn Việt Lâm
Giáo viên
14 tháng 9 2021
a.
\(\Leftrightarrow3sin3x-4sin^34x-\sqrt{3}cos9x=2sin2x\)
\(\Leftrightarrow sin9x-\sqrt{3}cos9x=2sin2x\)
\(\Leftrightarrow\dfrac{1}{2}sin9x-\dfrac{\sqrt{3}}{2}cos9x=sin2x\)
\(\Leftrightarrow sin\left(9x-\dfrac{\pi}{3}\right)=sin2x\)
\(\Leftrightarrow\left[{}\begin{matrix}9x-\dfrac{\pi}{3}=2x+k2\pi\\9x-\dfrac{\pi}{3}=\pi-2x+k2\pi\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{\pi}{21}+\dfrac{k2\pi}{7}\\x=\dfrac{4\pi}{33}+\dfrac{k2\pi}{11}\end{matrix}\right.\)
Help mik đi mik tick cho
\(\dfrac{2}{7}=\dfrac{10}{35}=\dfrac{12}{42}=\dfrac{16}{56}\)