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4 tháng 9 2023

Để chứng minh QO⋅QMOP⋅PM=HF^2/HE^2, ta sẽ sử dụng định lí hình học và tính chất của các tam giác đồng dạng.

Đầu tiên, ta cần chứng minh tam giác QOM và tam giác MOP đồng dạng. Ta có:

∠QOM = ∠MOP (do chúng là góc đối) ∠OQM = ∠OMP (do chúng là góc ở chung) => Tam giác QOM đồng dạng với tam giác MOP theo định lí góc-góc (AA).

Từ đó, ta có tỷ lệ giữa các cạnh của hai tam giác này:

QM/OP = OQ/OM (tỷ lệ cạnh tương ứng của hai tam giác đồng dạng) => QM = OQ/OM * OP

Tiếp theo, ta cần chứng minh tam giác HEF và tam giác HOM đồng dạng. Ta có:

∠HEF = ∠HOM (do chúng là góc đối) ∠EHF = ∠OHM (do chúng là góc ở chung) => Tam giác HEF đồng dạng với tam giác HOM theo định lí góc-góc (AA).

Từ đó, ta có tỷ lệ giữa các cạnh của hai tam giác này:

HE/OM = EF/OM (tỷ lệ cạnh tương ứng của hai tam giác đồng dạng) => HE = EF/OM * OM => HE = EF

Như vậy, ta có HE = EF.

Bây giờ, ta sẽ xem xét tỷ lệ giữa các đoạn thẳng QO, QM, OP, PM và HF, HE:

QO⋅QMOP⋅PM = (OQ/OM * OP) * (OP) * (PM) = OQ * OP * PM / OM = OQ * PM

Vì HE = EF, nên ta có:

HF/HE = QM/OM (tỷ lệ cạnh tương ứng của hai tam giác đồng dạng HEF và HOM) => HF = QM/OM * HE

Thay giá trị của HE = EF vào, ta có:

HF = QM/OM * EF

Vậy, ta thấy HF^2 = (QM/OM * EF)^2

Như vậy, ta có:

QO⋅QMOP⋅PM = HF^2/HE^2

Vậy, điều phải chứng minh đã được chứng minh.

1
5 tháng 5 2019

1. As a result of his negligent driving, the accident happened.

2. Owing to the changing of the management, he lost his job.

3. On account of her good behavior, everybody loves her.

4. Because of my inability to read Russian, I have had to have the documents translated to French.

5. They got high pay because of their good work.

6. Because I can't hear the speaker, I moved to the front row.

7. Even though she had told the truth, the policeman didn't believe her.

8. Because of the obstacles, the building didn't go along as planned.

1
20 tháng 1 2019

Vừa làm rồi nhé em gái :)

Câu hỏi của bùi hoàng yến - Tiếng anh lớp 9 | Học trực tuyến

Chúc em học tốt ><

IV.  Write a sentence with wish for each situation:1. My family usually went to the pagoda on the first day of the new year. Now we don’t do that anymore.àI wish 2. There’s a handicraft exhibition in my school tomorrow but I can’t go because I’m still sick.à 3. I’m going to my hometown for the summer holiday. But there isn’t Internet there so it will be boring.à4. Sometimes I want to come back to my childhood so that I can play traditional games with my friends.à5. Trung really...
Đọc tiếp

IV.  Write a sentence with wish for each situation:

1. My family usually went to the pagoda on the first day of the new year. Now we don’t do that anymore.

àI wish

2. There’s a handicraft exhibition in my school tomorrow but I can’t go because I’m still sick.

à

3. I’m going to my hometown for the summer holiday. But there isn’t Internet there so it will be boring.

à

4. Sometimes I want to come back to my childhood so that I can play traditional games with my friends.

à

5. Trung really likes the new speaker model, but it is too expensive for him to afford it.

à

6. You are driving too dangerously!

à

7. I used to suffer from school-bullying because I was weak and too shy.

à

8. I feel bored as I was born and grew up in a poor countryside.

à

9. We lost the match because we didn’t try our best.

à

10. My father said that he missed his first job regretfully.

àMy father wished
giúp mình gấp với ạ

0
1. My _ _ _ n _ of view is completely different from yours. I disagree with you.2. Maybe your sister will _ e _ _ us some cash if we promise to give it back soon.3. It’s a miracle that all the passengers _ _ _ v _ _ _ d the rail accident. A few of them had broken ribs and legs but most of them had just bruises.4. Mandy’s hair is not curly. It’s _ _ r _ _ _ h _.5. The invitation to the Presidential Palace and the meeting with the President has been the most memorable _ _ e _ _ in my...
Đọc tiếp
1. My _ _ _ n _ of view is completely different from yours. I disagree with you.
2. Maybe your sister will _ e _ _ us some cash if we promise to give it back soon.
3. It’s a miracle that all the passengers _ _ _ v _ _ _ d the rail accident. A few of them had broken ribs and legs but most of them had just bruises.
4. Mandy’s hair is not curly. It’s _ _ r _ _ _ h _.
5. The invitation to the Presidential Palace and the meeting with the President has been the most memorable _ _ e _ _ in my life so far.
6. Let me think before I make a _ _ o _ _ _.I think I will buy the white dress. Or maybe the black skirt. I don’t know myself.
7. Look at those clouds. It’s _ _ k _ _ y to rain in the afternoon. We’d better take our umbrellas.
8. This vacuum cleaner is rather expensive but the high quality of work is its biggest _ _ v _ _ _ a _ _.
9. In this strategic game, you have several military missions to _ _ _ r _ out. None of them is easy, though.
10. You may not take part in the discussion. You are not a _ _ m _ _ r of the club.
0
12 tháng 9 2021

1. on

2. would

3. turn

4.makes

5. belong

6.if

7. ago

8. whose

9. only

10. taking

I. Turn these sentences into Reported speech.1. She said,” I can’t find my umbrella”2. They said, “We are learning English now”3. “ My friend is coming next week”, Tom said.4. “ I’ll help my mum with housework this weekend”5. “We shall overcome this difficulty”, they saidII. Change Yes/ no question into reported speech: 1. She asked me, “Do you like Marlon Brando?”2. I said to him, “Are you a foreigner?”3. He asked her, “Have you met Danny yet?”4. He...
Đọc tiếp
I. Turn these sentences into Reported speech.
1. She said,” I can’t find my umbrella”
2. They said, “We are learning English now”
3. “ My friend is coming next week”, Tom said.
4. “ I’ll help my mum with housework this weekend”
5. “We shall overcome this difficulty”, they said
II. Change Yes/ no question into reported speech: 
1. She asked me, “Do you like Marlon Brando?”
2. I said to him, “Are you a foreigner?”
3. He asked her, “Have you met Danny yet?”
4. He asked me, “Did you borrow my dictionary?”
5. They said to me, “Does your father work here?”
III Change WH QUESTIONS  into reported speech:
21. He asked me: “Who is Oliver Twist?”
  22. My mother asked me: “What‘s the matter with you?”
23. I asked him: “Which book do you find?”
24. He asked me: “When do you finish your work?”
25. Mai asked me: “Why didn’t you come?”
IV Change IMPERATIVE  into reported speech:
6. “Don’t go near the sea, children”. (The children’s mother warned)
7. “Don’t be late, Jim”. (Jim’s father told)
8. “Be quiet, children”. (The librarian told)
9. “Don’t shoot!” (The officer ordered me)
10. “Don’t use the telephone after 7.00”. (The landlady told us)
 
0
6 tháng 11 2016

1, I am having my car serviced by the garage on Monday.

2, He is believed to be mad.

3, No matter how hard I tried, I just couldn't get the money.

2 tháng 11 2016

.

3 tháng 5 2021

Chào em, em tham khảo nhé!

Question 46. Although she had an injured ankle, Esther still won the tennis match.

Despite his injured ankle, Esther still won the tennis match.

Question 47. It was such a long journey that they were all asleep by the time they arrived.

The journey was so long that they were all asleep by the time they arrived.

Question 48. The luggage is too heavy for her to carry.

The luggage is so heavy that she cannot carry it.

Question 49: Do you know the man who sat next to me at Nam’s birthday party last night?

You know the man who sat next to me at Nam's birthday party last night, don't you?

Question 50: Don’t forget to bring your passports with you when you go abroad.”

She reminded me not to forget to bring my passports with me when I went abroad.

Chúc em học tốt và có những trải nghiệm tuyệt vời tại olm.vn!

Question46. Although she had an injured ankle, Esther still won the tennis match.

Despite Esther's  injured ankle, she still won the tennis match.

Question 47. It was such a long journey that they were all asleep by the time they arrived.

The journey was so long that they were all asleep by the time they

Question 48. The luggage is too heavy for her to carry.

The luggage is so heavy that she can't carry

Question 49: Do you know the man who sat next to me at Nam’s birthday party last night?

You know the man who sat next to me at Nam’s birthday party last night,don't you?

Question 50: Don’t forget to bring your passports with you when you go abroad.”

 She reminded me to bring my passports with me when I go abroad.