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12 tháng 5 2021

Áp dụng BĐT Bunhiacopxki cho 2 bộ số (\(\sqrt{a+b}\),\(\sqrt{b+c}\),\(\sqrt{a+c}\)) và (1,1,1) có: (1.\(\sqrt{a+b}\)+1.\(\sqrt{b+c}\)+1.\(\sqrt{a+c}\))2 ≤ (a + b + b + c + c + a)(12 + 12 + 12)

=> S2 ≤ 2.3 = 6 ⇔ S ≤ \(\sqrt{6}\)

Dấu "=" xảy ra ⇔  \(\sqrt{a+b}\) = \(\sqrt{b+c}\) = \(\sqrt{a+c}\) ⇔ a +b = b + c = c + a

                                                                          ⇔ 1 - c = 1 - a = 1 - b

                                                                          ⇔ a = b = c = \(\dfrac{1}{3}\) 

Vậy maxS = \(\sqrt{6}\)  ⇔ a = b = c = \(\dfrac{1}{3}\) 

 

24 tháng 9 2021

ta có ∠1=70o(hai góc đối đỉnh)

hai đường thẳng a và b cùng cắt c tạo thành 30o+150o=180omà hai góc ở vị trí trong cùng phía

=>a//b(dấu hiệu)

=>∠1=∠2(hai góc đồng vị) ta lại có: ∠1=70o(cmt)=>∠2=70o

mà ∠2=∠3(hai góc đối đỉnh)=>∠3=70o

bài hơi khó hiểu(tại bạn không ghi rõ tên góc đó)

9 tháng 9 2021

Refer

1. “Your cousin speaks English very well” Paul told me

Paul said that ___________my cousin spoke English very well____________

2. “The man broke out of prison yesterday” said the policeman

The policeman told us_that the man had broken out of prison the day beforr__

3. “I’ll lend you this book as soon as I finish it” Owen said to me

Owen said __me that he would lend me that book as soon as he finished it___

4. “I think I forgot to turn off the lights this morning” Brenda told Brian

Brenda told Brian ____that he thought he had forgotten to turn off the lights that morning.____

5. “I work eight hours a day, except when the children are on holiday” said Mrs. Wood

Mrs. Wood said me that he worked eight hours a day, excepted when the children were on holiday

6. “You’ve been making good progress this semester” Miss Lynn told me

Miss Lynn said that _____I had been making good progress that semester_________

7. “If you bought all the tickets, you would win the lottery” the man said

The man told me ______that If I had bought all the tickets, I would win the lottery______________

8. “I like swimming but I don’t go very often” Jill said to Pam

Jill said that ______he liked swimming but he didn’t go very often___________________________

9. “I want to buy it, but I haven’t brought any money” said Patrick

Patrick told me _________that he wanted to buy it, but he hadn’t brought any money_______________________

10. “I’m going to visit my aunt in Hue, but I’m not sure when” said Mai

Mai told me _________that she was going to visit her aunt in Hue, but she was not sure when__________________

a: 4/25=16/100

-7/4=-175/100

9/50=18/100

b: -7/10=-28/40

11/20=22/40

-10/40=-10/40

c: 5/18=10/36

7/12=21/36

11/6=66/36

3 tháng 3 2023

em ơi chưa có bài em nhé, em chưa tải bài lên lám sao mình giúp được 

3 tháng 3 2023

Dạ đề đây ạ loading...  

13 tháng 12 2021

\(=2x^2\left(x-1\right)-4x\left(x-1\right)=\left(x-1\right)\left(2x^2-4x\right)=2x\left(x-2\right)\left(x-1\right)\)

13 tháng 12 2021

cám ơn bạn nhá :)