giúp mình tính tích phân những con này với ạ: a/ cận 0-> π/2 : [cos^3(x) - 1] . cos^2(x) dx b/ cận 0->π/6 : tan^4(x)/cos2x dx c/ cận 0 -> π/4 : x/(1+cos2x) dx

tìm công thức phân tử biết thành phần phần trăm về khối lượng của: a) Hợp chất (x) có 40%C; 21,6%H; 38,4%O, khối lượng mol của(x) là 180g/mol b) Hợp chất (y) có 81,82%C, khối lượng mol của(y) là 44g/mol

Giúp mình với cb,sau kì nghỉ tế dài dài, mình đã kb gì về nó. Tối nay phải nộp ngay cb ạ.Help me 😭

(x-1)(3x+1)=0 (X-1)(x+2)(x-3)=0

Gọi M,N là 2 điểm trên (O;R) và a,b là 2 tiếp tuyến tại M,N. Trên đường thẳng vg với mặt phẳng chứa (O) tại O ta lấy S sao cho SO=R.Tính góc giữa (S,a) và (S,b) trong các trường hợp sau a)M,N là 2 đầu của một đường kính b) Tam giác MON vuông

mọi người giải thích cho em với sao lại loại công sai và công bội chứ ạ, em nhớ chúng âm dương đều được ?

De keo truc tiep 1 thung nuoc co Khoi Lương8 kg Tủ duo I Len Thông qua 1 soi day, at phai tac dung luc co Phuong, chieu, do LƠN Ngu the nao Len soi day

đặt đại từ quan hệ thích hợp vào câu sau 40. The song is about two young lovers. Their romance ended happily. => 41. Charlie Chaplin died in 1977. His films amused millions. => 42. I love this song. Catherine sang it. => 43. My parents gave me a birthday present. I like it. => 44. I love his song. The song was written by Catherine. => 45. I want to know about Mss. Green. She has just won a gold medal. => 46. This is a new hotel. There are modern facilities in it. => 47. I’ve lost my ticket. It cost five pounds. => 48. The headmaster spoke to the boys. Their work was below standard. => 49. The secretary wrote me a letter. She knows Fred. => 50. Family dinner often served at 7 o’clock. It’s the biggest meal of the day. => 51. My sister wants to speak to you. You met her yesterday. => 52. It is that man. He wrote this novel. => 53. This doesn’t show the place. The birds come from that place. => 54. The old man has died. You were talking to me about him. => 55. He sat on the table. One leg of the table was nearly broken down => 56. Hoan Kiem Lake is a historical place. Its water is always blue. => 57. He can change the situation. He always likes to do something new. => 58. That is just the thing. I didn’t want it to happen. => 59. You lost a key. Did you find it? => 60. Jill is wearing a jacket. I like it. => 61. I gave you some money. Where is it? => 62. She told a story. I didn’t believe it. => 63. You bought some oranges. How much were they? => 64. You gave me an umbrella. I’ve lost it. => 65. They invited some people to dinner. The people didn’t come. => 66. My secretary is a man. He can speak 2 languages. => 67. Some people live next door to us. They are very nice. => 68. Then a man passed me. He was driving a large modern car. => 69. I saw some people. Their car was broken down. => 70. This is a photograph of our classmates. We went on holiday with them. => 71. Jack has a brother. All of them are married. => 72. Ann has a lot of books. She hasn’t read most of them. => 73. A bus crashed into a van yesterday. It was carrying 30 passengers. => 74. When I was walking home, there was a man. He was following me. => 75. I was woken up by the baby. She was crying.

Chỉ mình cách giải bài trong ảnh

HELP ME PLS! Cho tam giác ABC có 5C = A+B. Tính số đo các góc A, B ,C biết A:B= 2:3