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Giải phương trình $cos^{3}x+$ $cos^{2}x-$ $4cos^{2}\frac{x}{2}=0$ giúp mình với

câu tường thuật 1. “Is a return ticket cheap tonight?” my uncle said. 2. “Do these puppies travel free?” a dog owner asked. 3. “Can I bring my dog into the plane with me?” she asked him. 4. “Does this train stop at York?” Bill told me. 5. “Can you telephone from inter – city trains?” businessman said. 6. “Does the 2.40 train have a business room?” he said. 7. “Can you get coffee on the train?” my aunt asked.

Tìm 5 phân số mà giá trị của mỗi phân số đó lớn hơn -1/3 và nhỏ hơn -1/4.

A/ and I went with three friends B/ but I got up early and went to C/ but we didn’t mind D/ because I couldn’t find it when I got on the coach E/ because for four of us it was our first time away from home F/ so we decided to travel by coach G/ so we went to Hyde Park for a game of football The first time I went abroad was when I went to London. It was in the summer holidays about five or six years ago (0) A . The plane and train were quite expensive, (1)_______. We left at five o’clock in the morning and the journey to London took about sixteen hours, (2)_______: we were all very excited (3)_______. We stayed in London for three days, in a youth hostel not far from the center. While we were there, we walked a lot. We went to see all the famous sites – Big Ben, Piccadilly Circus, Buckingham Palace and so on. On the last morning, my friends stayed in bed late, (4)_______ Camden Market. You can buy all things of jewelry and clothes there. It was really hot and sunny in the afternoon, (5)_______. I’ve been back to London several times since then, but I don’t think I’ll ever feel as excited as I did that first time.

Công thức hóa học của nhóm Hidroxit là gì vậy ạ???

Bài 5. Cho tam giác ABC vuông tại A. Gọi D và E lần lượt là trung điểm của AB và BC. a) Chứng minh tứ giác ACED là hình thang vuông. b) Gọi F là điểm đối xứng của E qua D. Chứng minh ACEF là hình bình hành. c) Chứng minh AEBF là hình thoi

Làm nhanh giúp mk chiều mk cần gấp r

mình cần giúp mn ơi hứa vote thank mn

Kiểm tra xem giá trị x = 2 có là nghiệm của bất phương trình 3x2< 5 hay không?