A=(1-1/2).(1-1/3).....(1-1/n+1) với n thuộc N

Ngay sau thắng lợi của cuộc kháng chiến chống Mỹ cứu nước, để bảo vệ lãnh thổ của Tổ quốc, Việt Nam phải đối đầu trực tiếp với những lực lượng xâm lược nào? A. Tập đoàn Pôn Pốt, quân xâm lược Trung Quốc B. Quân xâm lược Pháp, Trung Quốc C. Quân xâm lược Mỹ, Pôn Pốt D. Quân xâm lược Nhật, Trung Quốc

Ai giúp mình được không mình cần gấp ạ

vẽ anime/chibi có tâm nl: ai báo mod giúp mình bạn buff này với, link -cmt

Giúp mình với mn ơi . Mình cảm ơn ạ !

Vẽ chibi/mầm Y/c: đẹp, có tâm, digi Nl: rảnh quá không có gì làm :>

Tìm các số tự nhiên lẻ sao cho a=n^2012 +1 là số chính phương

31. A small stone struck the windshield while we ________ down the road. A. drive B. were driving C. had driven D. had been driving 32. Mr. Hân is going to the USA for his holiday. He ________ up for nearly a year now. A. has saved B. is saving C. saves D. has been saving 33. The carpet ________. A. hasn’t been cleaned yet. B. hasn't cleaned yet. C. have yet been cleaned. D. has cleaned. 34. "Did you have a good time abroad?" - She asked me if ________. A. I have a good time abroad. B. I had good time abroad. C. I had had a good time abroad. D. I have had a good time abroad. 35. ________ this letter ________ last night? A. Is/ written B. Is/ wrote C. Was/ written D. Were/ written 36. The houses where I used to live ________ very comfortable. A. is B. was C. are D. were 37. After he ________ English course, he went to England to continue his study. A. will finish B. has finished C. had finished D. have been finished 38. I wish I ________ a trip to London last year. A. had taken B. took C. will take D. take 39. He started living here three years ago. A. He lived here three years ago. B. He has lived here for three years. C. He had been living here for three years. D. He had lived here three years ago. 40. Who ________ when I came? A. were you talking to B. are you talking to C. you are talking to D. you were talking to 41. Please send us a post card as soon as you ________ in London. A. will arrive B. is going to arrive C. arrive D. arrived 42. Now he ________ a book about English. I don’t think he will finish it. A. writes B. wrote C. has written D. is writing 43. The foreign guest ________ here almost a week. A. was B. are C. has been D. is 44. Look! The two boys ________ your window. A. were painting B. painting C. are painting D. have painted 45. Before he ________ to bed, he ________ his homework. A. went/ has done B. went/ had done C. goes/ have done D. goes/ did

chứng minh các biểu thức sau ko phụ thuộc bào biến x (x+1)^3-(x-1)^3-6(x+1)(x+1)

Tính giá trị biểu thức sau x(x2+y+1)−y(x−y+1) tại x=1,y=1 giups mik voiws mik cần gấp