HOC24
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Trong không gian với hệ tọa độ Oxyz , cho hai vectơ a → ( 0 ; 3 ; 1 ) và b → ( 3 ; 0 ; − 1 ) . Tính cos ( a , → b → ) .
A. cos ( a → , b → ) = − 1 100 .
B. cos a → , b → = 1 100 .
C. cos ( a → , b → ) = 1 10 .
D. cos a , → b → = 1 10 .
x thuộc { 2;4;8;22}
tick nhé
2 cap ! Bạn cũng giải giúp mình bài toán mình gửi nha!
Choose a, b, c or d to complete these sentences.
Tom said that he_________ in the city.
a. living
b. to visit
c. visited
d. visiting
Cho hình nón có thể tích 100 π và chu vi đáy là 10. Tính độ dài đường sinh
A. 12
B. 20
C. 13
D. 14
The average lifespan of the Japanese is 78 for males and 85 for females, the longest in the world. The main secret lies in their food. The Japanese eat a lot of tofu, which is made from soybeans. Tofu contains a lot of vegetable protein, calcium and Vitamin B. It doesn’t contain much fat, and it doesn’t provide many calories. Seafood and vegetables play an important role in their diet, too. They cook the seafood with less cooking oil and less time. For each meal, they have more dishes on the table than us but they eat only a little of everything, never stuffing themselves.