giai giup em voi?
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Những câu hỏi liên quan
LN
4
DT
Đỗ Thanh Hải
CTVVIP
15 tháng 4 2021
1 Japanese is too difficult for me to learn
2 If he felt well, he wouldn't go to bed early
3 I wish I hadn't gone out in the rain
4 They had me carry te box upstairs
5 Your sister is too young to enjoy this film
6 THey had this letter posted by me
7 The morning was too cold for them to go out
8 If the tickets were cheap enough, we would go there
9 The pupils collected these old clothes
10 The coffee is so excellent so I can drink it
DT
Đỗ Thanh Hải
CTVVIP
15 tháng 4 2021
11 Her house was sold 2 years ago
12 Some tickets was bought there by him
13 Waste paper was recycled to save money and labour
14 The TV set was so heavy that the girl couldn't move it
15 I will have someone type the report for you
16 There was so much fog that the driver couldn't see far
17 THe day was fine enoigh for them to enjoy sunbathing on the beach
18 I wish your were here now
19 Susan offeref me to lend her some money
20 They asked me is I could fill in the form
TT
2
TT
2
DT
Đỗ Thanh Hải
CTVVIP
25 tháng 5 2021
Đề dài thế này sao giải thích nhanh cho e đc
Part 1
1 C
2 B
3 D
4 C
5 B
6 A
Part 2
1 T
2 F
3 F
4 F
V
1 That old house has just been bought
2 If he doesn't take these pills, he won't be better
3 I suggest taking a train
4 Spending the weekend in the countryside is very wonderful
TT
2
DT
Đỗ Thanh Hải
CTVVIP
24 tháng 5 2021
1 The meeting was canceled 3 days ago
2 She told me she was watching a film with her sister then
3 I admire the guitarist who is perfroming on the stage
4 Had it not been for Pauline's interest, the project would have been abandoned
NT
5
NV
Nguyễn Việt Lâm
Giáo viên
22 tháng 10 2021
b.
\(\Leftrightarrow\dfrac{1}{2}cosx-\dfrac{\sqrt{3}}{2}sinx=-\dfrac{1}{2}\)
\(\Leftrightarrow cos\left(x+\dfrac{\pi}{3}\right)=-\dfrac{1}{2}\)
\(\Leftrightarrow\left[{}\begin{matrix}x+\dfrac{\pi}{3}=\dfrac{2\pi}{3}+k2\pi\\x+\dfrac{\pi}{3}=-\dfrac{2\pi}{3}+k2\pi\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{\pi}{3}+k2\pi\\x=-\pi+k2\pi\end{matrix}\right.\)
NV
Nguyễn Việt Lâm
Giáo viên
22 tháng 10 2021
c.
\(\Leftrightarrow\dfrac{3}{5}sinx-\dfrac{4}{5}cosx=1\)
Đặt \(\dfrac{3}{5}=cosa\) với \(a\in\left(0;\dfrac{\pi}{2}\right)\Rightarrow\dfrac{4}{5}=sina\)
Pt trở thành:
\(sinx.cosa-cosx.sina=1\)
\(\Leftrightarrow sin\left(x-a\right)=1\)
\(\Leftrightarrow x-a=\dfrac{\pi}{2}+k2\pi\)
\(\Leftrightarrow x=a+\dfrac{\pi}{2}+k2\pi\)
NT
1
j