Cho dãy số (Un) có tổng n số hạng đầu là \(S_n=3^n-1\)

Tính \(S=2u_1+3u_2+4u_3+...+2011.u_{2010}\)

Gọi \(x_1;x_2;...;x_n\) là tất cả các nghiệm của phương trình \(cos1009x-cos1008x=0\) với \(0< x< \pi\)

Tính tổng \(S=cosx_1+cosx_2+...+cosx_n\)

Cho \(x;y\in R\) thỏa mãn \(x^2+y^2-2x-4y+4=0\)

Tìm giá trị lớn nhất,giá trị nhỏ nhất của biểu thức

\(P=x^2-y^2+2\sqrt{3}xy-2\left(1+2\sqrt{3}\right)x+\left(4-2\sqrt{3}\right)y-3+4\sqrt{3}\)

1. ………………… are non-renewable energy sources such as coal, fuel oil and natural gas formed from dead plants and animals underground.

A. greenhouse effect B. global warming C.deforestation D. Fossil fuels

2. Using a/an ………………………. device such as a laptop, you can learn English effectively.

A. electric B. electronic C. electricity D. electrical

3. A_____forest is a forest where trees that are cut are replanted and the wildlife is protected.

A. tropical B. ecological C. sustainable D. sub-tropical

4. Like children elsewhere, children in the USA have greatly benefited ________ modern technology.

A. in B. from C. since D. for

5. ………..is the removal or cutting down of all trees in an area for urban use and farm lands.

A. Forest B. Deforest C. Deforestation D. Foresting

6. Water ……………………….are things like detergents, pesticides ,oils and other chemicals that make the water unclean and contaminated.

A. pollution B. pollutants C. deforestation D. Fossil fuels

7. I like students …….have a good sense of humour.

A. who B. whom C. whose D. which

8. Mary : -Thank you for your help, Jane.

Jane : _ …………………………

A. You are right B. Not at all C. Of course. D. You’re welcome.

9. The doctor said to Peter: “Don’t go for a walk today”

A. The doctor said Peter not to go for a walk that day. ....................... B. The doctor told Peter not go for a walk that day.

C. The doctor said to Peter not to go for a walk that day.................. D. The doctor told Peter not to go for a walk that day.

10. Thomas: “ Do you feel like going to the cinema tonight?” Susan: “ _______________”
A. I don’t agree. I’m afraid B. You’re welcome

C. That would be great! D. I feel very bored.

11. The editor asked Nam …………… some practical advice on the preservation of the environment.

A. to write B. writing C. write D. written

12. The________of the ozone layer is not a good thing for the earth.

A. depletion B. deplete C. depleting D. depletement

13. The_______of fossil fuels has gradually increased in many countries which is concerned for many environmentalists.

A. consumer B. consume C. consuming D. consumption

14. Deforestation will lead to the extinction of rare animals due to the loss of their habitats, and extreme floods and land _________.

A. erode B. eroding C. erosion D. erodement

15. The smoke from burning fuels causes pollution if it ______ into the atmosphere.

A. releases B. is released C. will be released D. released.

16. Students can download programme and………………from internet.

A. materials B. food C. drink D. note

17. Mass tourism has contributed to the _____of the environment.

A. destroy B. destroying C. destruction D. destroyment

18. Consumers have been encouraged to use _____products.

A. environment friendly B. environmental friendly

C. environmentally friend D. environmentally friendly

19. _______ aren't effective anymore because insects have become resistant to them.

A. Fertilizers B. Pesticides C. Herbicides D. Medicines

20. I like students ________have a good sense of humour.

A. who B. whom C. whose D. which

21. The teacher asked students _________ a paragraph about the preservation of the environment.

A. to write B. writing C. write D. written

22. I wonder ỉf you could help me.” “_________”

A. Don’t mention it C. I’ll do my best. What’s up?

B. Really? How nice D. No, what is it?

23. The Vietnamese government has done a lot to____________ hunger and poverty.

A. eliminate B. increase C. protect D. keep

24. Personal electronic devices can be very _______, to you and to others.

A. distractal B. distract C. distractional D. distracting

25. Most chemicals .............................the ground and the underground water.

A. contaminates B. contaminate C. contamination D. contaminating

26. The team paid a ________ price for its lack of preparation.

A. heavy B. light C. dirty D. expensive

27. Health is ________________ than money.

A. the important B. most important C. more important D. importanter

28. In the past, the proposal and engagement ceremonies took place 1 or 2 years ________ the wedding.

A. before B. after C. while D. since

29. We _________ stop when traffic lights are red.

A. might B. should C. must D. can

30. Gender discrimination should be ____________ so that everyone has equal opportunities in education.

A. eliminated B. eliminate C. elimination D. eliminating

31. Superstitions still________ an important part of life for many people in Vietnam.

A. do B. take C. play D. give

32. We had dinner in________ most expensive restaurant in town.

A. an B. x C. the D. a

33. The flight stops at Hong Kong before going on to its final_____

A. destination B. target C. stop D. arrival

34. There is a wedding _________ for all the guests after the wedding ceremony.

A. proposal B. anniversary C. reception D. celebration

35. My house is________hers.

A. cheap than B. cheaper C. more cheap than D. cheaper than

36. My cousin's ______ is next Sunday.

A. marriage B. wedding C. tradition D. assignment

37. There is a wedding ______ for all guests after the wedding ceremony.

A. reception B. engagement C. proposal D. ring

38. We should not allow any kind of discrimination ____________ women and girls.

A. of B. at C. in D. against

39. My brother likes playing_________ football while my sister is interested in playing ________ piano.
A. the/ the B. 0 / the C. the / 0 D. 0/0

40. In Portugal, walking backwards will bring bad luck, because it paves _____way for _____devil to enter.

A. a-a B. the-the C. a-the D. the-a

41. I believe gender ____________ in education starts at home

A. discriminate B. discrimination C. discriminator D. discriminative

42. Men are ____________ leaders than women

A. good B. better C. best D. bad

43. Women will be ____________ if they have to do two jobs: at work and at home.

A. exhaust B. exhausted C. exhausting D. exhauster

44. The bride and groom are surely the ____________ people on their wedding day.

A. happy B. happier C. happily D. happiest

45. In order to ________ a man’s job, Brenda had to work very hard.

A. pursue B. work C. enroll D. prefer

46. Jim_____ the teacher that he would see her the next day.

A. said B. tells C. asked D. said to

47. If Eric _____5 years younger, he could travel around the world.

A. is B. were C. had been D. would be

48. E-books are typically _____through a student's personal device, such as a notebook, tablet, or cell phone.

A. addressed B. accessed C. affected D. identified

49. Several _____are known to cause cancer to develop.

A. chemists B. chemistry C. chemical D. chemicals

50. Only 40% of 5-year-olds have access _____pre-school education.

A. with B. for C. to D. in

I. Pronunciation: Choose the word whose primary stressed syllable is different from those of the rest.

1. A. finger B. consume C. deplete D. protect

2. A. confusion B. solution C. protection D. editor

3. A. animal B. invention C. energy D. influence

4. A. disappearance B. vulnerable C. conservation D. generation

5. A. identify B. disadvantage C. technology D. eliminate

6. A. diverse B. wildlife C. fauna D. flora

Choose the word whose underlined part is pronounced differently from the others:

7.A. survive B. prohibit C. fertilizer D.environment

8.A. tablet B. access C. application D. landscape

9.A. aquatic B. access C. altar D. ancestor

10. A. employment B. secondary C. eliminate D. women

11. A. editor B. access C. effect D. deplete

12. A. brochure B. chore C. church D. discharge

Xét các số thực x;y;z thỏa mãn \(x\left(x-1\right)+y\left(y-1\right)+z\left(z-1\right)\le\frac{3}{4}\)

Tìm GTNN ;GTLN của biểu thức P=x+y+z

Cho hai số thực dương x;y thỏa mãn \(x^2+y^2=1\) .Tìm giá trị lớn nhất của biểu thức: \(K=x\sqrt{3}+y\)

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