Cho hình thang ABCD , \(\widehat{A}\) = \(90^{\sigma}\) , \(\widehat{B}\) = \(90^{\sigma}\)
a. cho AB = 9cm , AD = 12cm , hãy
- giải tam giác vuông ADB
- tính AO , DO , AC
+ kẻ BH \(\perp\) DC tại H . Tính \(S_{DOH}\)
b. c/minh : \(BH^2\) \(\times\) CD ?
mn giúp mik nhé mik đang cần gấp
bài 1 : tính
A= \(\cos^220^{\sigma}\) + \(\cos^240^{\sigma}\) + \(\cos^250^{\sigma}\) + \(\cos^270^{\sigma}\)
B= \(\cos^2\alpha+\cos^2\alpha+\sin^{\sigma}\alpha+\cos^2\alpha\)
mn hộ mik nhé
mik cảm ơn
( lưu ý : \(\sigma\) : nhiệt độ
\(\alpha\) : am pha
chuyển các câu sau sang bị động
1. they told me that you were the best architect in this city
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2. she reported that the flowers were killed by frost
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3. some people inform me that the director is going to take a business trip to engand
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4. that officer announced that the meeting was delayed until next week
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5. he discovered that this cotton was grown in egypt
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6. they promise that the performance will start on time
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7. he recommends that we should stay at the city center
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8. we believed that alice would pass the driving test
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9. the director notifies that all the workers will have to work extra hard this month
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10. they persuade me that they will go with me to the stadium
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11. they decided that the company will go tothe beach together at the weekend
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12. people think that maradona is the best football player in the 20th century
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13.they find that the job is not suitale for a girl like her
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14. the teacher explained that this powerful engine pulled the train
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15. he told me that his football team had playd well last season
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mn giúp mik nha mik đang cần gáp cảm ơn mn nhìu
\(A=\frac{7}{\sqrt{X}+8}\)
\(B=\frac{\sqrt{X}}{\sqrt{X}-3}+\frac{2\sqrt{X}-24}{X-9}\)
( VỚI \(X\ge0,X\ne9\) )
a. tính giá trị của A khi x=25
b. chứng minh B =\(\frac{\sqrt{x}+8}{\sqrt{x}+3}\)
c. tìm \(x\in z\) để P=A.B có giá trị nguyên
d. tìm mã P = ?
e, tìm x để P = \(\frac{1}{2}\)
g. so sánh P với \(\frac{-1}{2}\)
mọi người giúp e với ạ e đang cần gấp
cảm ơn mn nhiều nha
Chuyển câu chủ động sang câu bị động !!
1. police were questioning Tom
=>____________________________________________________
2. he opens the mails every morning
=>________________________________________________
3. they are building a new school in this town
=>__________________________________________________
4. the fire has destroyed many houses
=>___________________________________________________
5. we finished the job by o'clock
=>____________________________________________________
6. they close the museum on monday
=>_________________________________________________
7. the police topped us on our way to school
=>__________________________________________________
8. people speak english all over the world
=>_____________________________________________________
9. they will build a new school next year
=>__________________________________________________________
10. john will deliver the letter
=>__________________________________________
11. he must do it right now
=>__________________________________________________
12. you should finish the report now
=>______________________________________________________
13. we shall discuss thê matter in the afternoon
=>_______________________________________________________
Mấy bạn giúp mik nhé!!
Cảm ưn mấy bạn