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9 tháng 6 2018

We have:\(\hept{\begin{cases}a^2+b^2+c^2=\frac{1}{3}\\a,b,c>0\end{cases}\Rightarrow0< a,b,c< \frac{1}{\sqrt{3}}}\)

We prove to:

\(4x+\frac{2}{3x}\ge-3x^2+\frac{11}{3}\)  with  \(0< x< \frac{1}{\sqrt{3}}\)

\(\Leftrightarrow4x+\frac{2}{3x}+3x^2-\frac{11}{3}\ge0\)

\(\Leftrightarrow9x^3+12x^2-11x+2\ge0\)

\(\Leftrightarrow\left(3x+1\right)^2\left(x+2\right)\ge0\)   Always true to all \(0< x< \frac{1}{\sqrt{3}}\) 

\(\Rightarrow VT\ge-3a^2+\frac{11}{3}-3b^2+\frac{11}{3}-3c^2+\frac{11}{3}\)

\(=-3\left(a^2+b^2+c^2\right)+11=-3.\frac{1}{3}+11=10\) \(\left(đpcm\right)\)

9 tháng 6 2018

Đặt biểu thức trên là \(A\)

Ta có : \(A=\left(4a+\frac{2}{3a}\right)+\left(4b+\frac{2}{3b}\right)+\left(4c+\frac{2}{3c}\right)\)

Cần chứng minh \(4a+\frac{2}{3a}\ge-3a^2+\frac{11}{3}\) (*)

Thật vậy \(BĐT\Leftrightarrow4a+\frac{2}{3a}+3a^2-\frac{11}{3}\ge0\)

\(\Leftrightarrow\frac{12a^2+2+9a^3-11a}{3a}\ge0\Leftrightarrow\frac{\left(a+2\right)\left(3a-1\right)^2}{3a}\ge0\) (luôn đúng)

Tương tự : \(4b+\frac{2}{3b}\ge-3b^2+\frac{11}{3}\)   và \(4c+\frac{2}{3c}\ge-3c^2+\frac{11}{3}\)

Cộng các bất dẳng thức vừa CM đc ta có :

\(A\ge-3\left(a^2+b^2+c^2\right)+\frac{11}{3}.3=-3.\frac{1}{3}+11=10\)

Dấu "=" xảy ra \(\Leftrightarrow a=b=c=\frac{1}{3}\)

13 tháng 4 2022

A

13 tháng 4 2022

Let's go shopping.

28 tháng 12 2021

B

28 tháng 12 2021

b

Crashing, hit a wallRight now I need a miracleHurry up now, I need a miracleStranded, reaching outI call your name but you're not aroundI say your name but you're not aroundI need you, I need you, I need you right nowYeah, I need you right nowSo don't let me, don't let me, don't let me downI think I'm losing my mind nowIt's in my head, darling I hopeThat you'll be here, when I need you the mostSo don't let me, don't let me, don't let me downD-Don't let me downDon't let me downDon't let me down,...
Đọc tiếp

Crashing, hit a wall
Right now I need a miracle
Hurry up now, I need a miracle
Stranded, reaching out
I call your name but you're not around
I say your name but you're not around

I need you, I need you, I need you right now
Yeah, I need you right now
So don't let me, don't let me, don't let me down
I think I'm losing my mind now
It's in my head, darling I hope
That you'll be here, when I need you the most
So don't let me, don't let me, don't let me down
D-Don't let me down

Don't let me down
Don't let me down, down, down
Don't let me down, don't let me down, down, down

R-r-running out of time
I really thought you were on my side
But now there's nobody by my side

I need you, I need you, I need you right now
Yeah, I need you right now
So don't let me, don't let me, don't let me down
I think I'm losing my mind now
It's in my head, darling I hope
That you'll be here, when I need you the most
So don't let me, don't let me, don't let me down
D-Don't let me down

Don't let me down
Don't let me down, down, down
Don't let me down, down, down
Don't let me down, down, down
Don't let me down, don't let me down, down, down

Oh, I think I'm losing my mind now, yeah, yeah, yeah
Oh, I think I'm losing my mind now, yeah, yeah

I need you, I need you, I need you right now
Yeah, I need you right now
So don't let me, don't let me, don't let me down
I think I'm losing my mind now
It's in my head, darling I hope
That you'll be here, when I need you the most
So don't let me, don't let me, don't let me down
Don't let me down

Yeah, don't let me down
Yeah, don't let me down
Don't let me down, oh no
Said don't let me down
Don't let me down
Don't let me down
Don't let me down, down, down    

_______________________

Dịch đi :) Cấm Google nha =)

6
3 tháng 7 2016

- Hahah: 10:00

3 tháng 7 2016

Google dịch thẳng tiến.

2 tháng 4 2022

I don't like this movie. Let's watch a funny one instead!

                                  Tạm biệt một thời gian, OLM.This night is cold in the kingdomI can feel you fade awayFrom the kitchen to the bathroom sink andYour steps keep me awakeDon't cut me down, throw me out, leave me here to wasteI once was a man with dignity and graceNow I'm slipping through the cracks of your cold embraceSo please, pleaseCould you find a way to let me down slowly?A little sympathy, I hope you can show meIf you wanna go then I'll be so lonelyIf you're leaving...
Đọc tiếp

                                  Tạm biệt một thời gian, OLM.

This night is cold in the kingdom
I can feel you fade away
From the kitchen to the bathroom sink and
Your steps keep me awake

Don't cut me down, throw me out, leave me here to waste
I once was a man with dignity and grace
Now I'm slipping through the cracks of your cold embrace
So please, please

Could you find a way to let me down slowly?
A little sympathy, I hope you can show me
If you wanna go then I'll be so lonely
If you're leaving baby let me down slowly

Let me down, down
Let me down, down
Let me down, let me down
Down, let me down, down
Let me down
If you wanna go then I'll be so lonely
If you're leaving baby let me down slowly

Cold skin, drag my feet on the tile
As I'm walking down the corridor
And I know we haven't talked in a while
So I'm looking for an open door

Don't cut me down, throw me out, leave me here to waste
I once was a man with dignity and grace
Now I'm slipping through the cracks of your cold embrace
So please, please

Could you find a way to let me down slowly?
A little sympathy, I hope you can show me
If you wanna go then I'll be so lonely
If you're leaving baby let me down slowly

Let me down, down
Let me down, down
Let me down, let me down
Down, let me down, down
Let me down
If you wanna go then I'll be so lonely
If you're leaving baby let me down slowly

And I can't stop myself from falling down
And I can't stop myself from falling down
And I can't stop myself from falling down
And I can't stop myself from falling down

Could you find a way to let me down slowly?
A little sympathy, I hope you can show me
If you wanna go then I'll be so lonely
If you're leaving baby let me down slowly

Let me down, down
Let me down, down
Let me down, let me down
Down, let me down, down
Let me down
If you wanna go then I'll be so lonely
If you're leaving baby let me down slowly

If you wanna go then I'll be so lonely
If you're leaving baby, let me down slowly

1
31 tháng 3 2021

Let me down của Alec Benjamin đúng không?

Which sentence is CORRECT?1. A. If he call, let me know.B. Should he call, let me know.C. Would he call, let me know.2. A. Were they to escape, there would be an outcry.B. Were they escaping, there would be an outcry.C. Were they escaped, there would be an outcry.3. A. If I had know, I would have protested strongly.B. Had I known, I would have protested strongly.C. Was I to have known, I would have protested strongly.4. A. Scarcely had it stopped raining than the sun came out.B. No sooner had...
Đọc tiếp

Which sentence is CORRECT?

1. A. If he call, let me know.

B. Should he call, let me know.

C. Would he call, let me know.

2. A. Were they to escape, there would be an outcry.

B. Were they escaping, there would be an outcry.

C. Were they escaped, there would be an outcry.

3. A. If I had know, I would have protested strongly.

B. Had I known, I would have protested strongly.

C. Was I to have known, I would have protested strongly.

4. A. Scarcely had it stopped raining than the sun came out.

B. No sooner had it stopped raining than the sun came out.

C. No sooner it had stopped raining than did the sun come out.

5. A. Not until did the mother come home that the boy stop crying.

B. Not until the mother came home that did the boy stop crying.

C. It was not until the mother came home that the boy stop crying.

6. A. Such the force of the storm was that trees were uprooted.

B. So was the force of the storm that trees were uprooted.

C. So much was the force of the storm that trees were uprooted.

7. A. Only by searching the Internet for the keys did he finish the homework.

B. By searching the Internet for the keys did he finish the homework.

C. Only by searching the Internet for the keys did he finished the homework.

8. A. Never have I seen this kind of creature before.

B. Never I have seen this kind of creature before.

C. Never do I see this kind of creature before.

9. A. Suddenly came down the rain!

B. Suddenly down came the rain!

C. Suddenly down did the rain come!

10. A. Difficult though it may be, it is not impossible.

B. Difficult although it may be, it is not impossible.

C. Difficult even though it may be is it not impossible.

11. A. Rarely do I have so much responsibility.

B. Rarely don’t I have so much responsibility.

C. Rarely do I not have so much responsibility.

12. A. Little the government appreciate what the results will be.

B. Little do the government appreciate what the results will be.

C. Little the government appreciates what the result will be.

13. A. Only Mary realized that the door was not locked.

B. Only Mary did realize that the door was not locked.

C. Only did Mary realize that the door was not locked.

14. A. At no time I was aware of anything out of the usual.

B. At no time was I aware of something out of the usual.

C. At no time was I aware of anything out of the usual.

15. A. In no condition are they to open fire without a warning.

B. At no condition are they to open fire without a warning.

C. On no condition are they to open fire without a warning.

16. A. Not only he sings well but he also plays musical instruments perfectly.

B. Not only does he sing well but he also plays musical instruments perfectly.

C. Not only he sings well but does he also play musical instruments perfectly.

17. A. In any way can the bus driver be blamed for the accident.

B. In no way can the bus driver not be blamed for the accident.

C. In no way can the bus driver be blamed for the accident.

18. A. On no account will I lend you the money.

B. On any account will I lend you the money.

C. In no account will I lend you the money.

19. A. Abby said that under no circumstances could Abby go out with her pals.

B. Abby said that under no circumstances Abby could go out with her pals.

C. Abby said that under no circumstances could Abby have gone out with her pals.

20. A. Not since 1994 anyone has won so many matches for his team.

B. Since 1994 no one hasn’t won so many matches for his team.

C. Not since 1994 has anyone won so many matches for his team.

0
Exercise 1 Choose the best answer.1. ________ good ice cream, youneed touse a lot of cream.a. Make b. Making c. To make d. For make2. I got my friend ________ her car for the weekend. a. tolet me toborrow b. to let me borrowc. let me borrow d. let me to borrow3. ‘How about going to the theater?' 'OK,' but I would rather ______ a concert.'a. attend b. to attend c. attending d. have attended4. The skiers would rather  ________ through the mountains than go by bus.a. to travel on train b. traveled...
Đọc tiếp

Exercise 1 Choose the best answer.

1. ________ good ice cream, youneed touse a lot of cream.

a. Make b. Making c. To make d. For make

2. I got my friend ________ her car for the weekend. 

a. tolet me toborrow b. to let me borrow

c. let me borrow d. let me to borrow

3. ‘How about going to the theater?' 'OK,' but I would rather ______ a concert.'

a. attend b. to attend c. attending d. have attended

4. The skiers would rather  ________ through the mountains than go by bus.

a. to travel on train b. traveled by train

c. travel by train d. traveling by the train

5. If we leave now for our trip, we can drive half the distance before we stop ___ lunch.

a. having b. to have c. having had d. for having

6. The examiner made us ___ our identification in order to be admitted to the test center.

a. show b. showing c. to show d. showed

7. I remember ________ to Paris when I was a very small child.

a. to be taken b. to take c. being taken d. taking

8. My parents wouldn't _______ to the party.

a. allow me go b. allow me to go    c. allow me going d. allow to go

9. We are going to have my house _______ tomorrow morning.

a. paint b. painting c. painted d. to be painted

10. We hope that the students themselves will enjoy ______ part in the projects.

a. to take b. taking c. to be taken d. being taken

1
14 tháng 8 2021

1 C

2 B

3 A

4 C

5 B

6 A

7 C

8 B

9 C

10 B

14 tháng 8 2021

cảm ưn nka 

26 tháng 1 2018

Given a segment AB = 100cm. Let C be a point between A and B. Let M, N be respectively the midpoint of the segment BC, AC. Find the length of the segment MN.  
Answer : MN = 50 cm 
P/s : k mình nha bạn

3 tháng 1 2022

C