Chọn đáp án sai trong các phép đổi đơn vị sau 450V= 0,45 kV.70mA = 0,7A.12mV = 0,012 V.4,5A = 4500 mA.

. Chất lỏng I có nhiệt độ t1 = 20 độ C, chất lỏng II có nhiệt độ t2. Đổ một khối lượng m1 chất lỏng I và một khối lượng m2 chất lỏng II vào cùng một bình nhiệt lượng kế thì nhiệt độ cân bằng của bình là tcb1 = 30 độ C. Đổ thêm một khối lượng m1 chất lỏng I vào bình nhiệt lượng kế thì nhiệt độ cân bằng của bình là tcb2 = 26 độ C. Hỏi nếu tiếp tục đổ thêm một lượng 3 m2 chất lỏng II vào bình thì nhiệt độ cân bằng của bình tcb3 là bao nhiêu? Coi như chỉ có sự trao đổi nhiệt giữa hai chất lỏng. Giúp mình ạ.

cho biểu thức P = 4/√a-1+3/√a+1-6√a+2/a-1 với a ≥ 0 , a khác 1 rút gọn biểu thức p tính giá trị biểu thức p khi = 6+2√5

Tìm đạo hàm của các hàm số sau :

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help me help me T_T_T_T_T_T pleaseeeee

Giúp em vs anh chị ơi em cho 5*

Để đo hiệu điện thế khoảng 5 V ta nên chọn vôn kế có giới hạn đo nào sau đây? 7,5 mV.5 mV.5 V.7,5 V.

Bài 5 (1 điểm): Hình thang vuông ABCD có A = D= 90°, AB = AD = 2 cm, DC = 4 cm. Tính số đo của góc ABC và góc BCD. Ai làm nhanh đúng 5 sao

1.We’ve never seen a prettier firework display before. A. This firework display isn’t as pretty as those we’ve seen. B. This is the prettiest firework display we’ve ever seen. C. This firework display is prettier than some we’ve ever seen. D. This is one of the prettiest firework displays we’ve ever seen. 2. Ann drives more carefully than Joe does. A. Joe drives as carefully as Ann does. B. Joe doesn’t drive so carefully as Ann does. C. Joe is a more careful driver than Ann. D. Joe drives more carefully than Ann. 3. Cristiano Ronaldo is much richer than any footballers else I have known. A. Cristiano Ronaldo is the richest footballer in the world. B. Cristiano Ronaldo is one of many very rich footballers in the world I have known. C. Cristiano Ronaldo is by far the richest footballer I have known. D. Cristiano Ronaldo is richer than all footballers . 4. There was more coffee in the refrigerator than now A. There is more coffee in the refrigerator than before. B. There is less coffee in the refrigerator than before. C. There is as much coffee in the refrigerator as before. 5. Ankara is only smaller than Istanbul, the biggest city in Turkey. A. Ankara is the second biggest city in Turkey. B. Ankara is bigger than Istanbul. C. Ankara is the biggest city in Turkey. D. Ankara is as big as Istanbul. 6. The test we did last time was more difficult than this one. A. We did an easy test last time and a difficult one this time. B. This test is not as difficult as the one we did last time. C. This time we have to do the most difficult test of all. D. The test we have done this time is not difficult at all. 7. Nga is the most beautiful girl in my class. A. Everyone in my class is more beautiful than Nga. B. Nga is not as beautiful as everyone in my class. C. Nga is more beautiful than everyone in my class. D. No one in my class is more beautiful than Nga. 8. The houses are small so they are cheap. A. The smaller the houses are, the cheaper they are. B. The smaller the houses are, the cheap they are. C. The more small the houses are, the cheaper they are. D. The smaller the houses are, cheaper they are. 9. No one in his class is taller than him. A. He is the taller in his class. B. He is tallest in his class. C. He is the tallest in his class. D. He is the shortest in his class. 10. Nam studies English better than Linh. A. Nam isn’t as good at English as Linh. B. Linh isn’t as good at English as Nam C. Nam is worse at English than Linh. D. Linh isn’t as bad at English as Nam. 11. Mr. Thompson is much richer than anyone else I have known. A. Mr. Thompson is the richest man in my country. B. Mr. Thompson is by far the richest man I have known. C. Mr. Thompson is richer than all his friends. D. Mr. Thompson is one of many very rich men I have known. 12. He is a much slower speaker than my brother. A. He speaks much more slowly than my brother. B. He doesn’t speak much more slowly than my brother. C. He speaks much more quickly than my brother. D. He doesn’t speak much more quickly as my brother. 13. China is the largest country in the Asia. A. No other country in the Asia is as large as Chinese. B. No other country in the Asia is as large than Chinese. C. Any other country in the Asia is larger than Chinese. D. China is as large as other countries in the Asia. 14. Mr David is by far the richest man I know. A. He is the richest man in my city. C. He is much richer than anyone else I know. B. He is one of many very rich men I know. D. He is richer than all his friends. 15. Peter is better at swimming than John. A. John isn’t as good at swimming as Peter. B. Peter isn’t as good at swimming as John. C. Peter is worse at swimming than John. D. John isn’t as bad at swimming as Peter. 16. I can’t cook as well as my mother does. A. My mother cook better than I am. B. My mother is a better cook than I am. C. My mother cooks as well as I do. D. My mother is a worse cook than I am.