Một chất điểm dao động điều hòa theo phương trình x = 4cos4t (cm). Thời gian chất điểm đi được quãng đường 8cm kể từ lúc bắt đầu dao động là: 

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Một số câu hỏi khác có thể bạn quan tâm.

• Find a mistake in the four underlined parts of the sentence and correct it:

  It is extremely important for an engineer to know to use a computer.

• Find a mistake in the four underlined parts of the sentence and correct it:

  Farmers look forward to participate in the county fairs.

• Find a mistake in the four underlined parts of the sentence and correct it:

  This is the person to that I sold my car.

• Find a mistake in the four underlined parts of the sentence and correct it:

  In spite of the car was cheap, it was in good condition.

• Find a mistake in the four underlined parts of the sentence and correct it:

  The tree which branches are dead should be cut down.

• Choose one sentence that has the same meaning to the root one:

  “He lost his job three months.”
  
  

• Choose one sentence that has the same meaning to the root one:

  “She hasn’t played the piano for five years.”
  
  

• Choose one sentence that has the same meaning to the root one:

  It is believed that the man escaped in a stolen car.
  
  

• Choose one sentence that has the same meaning to the root one:

  "Leave my house now or I’ll call the police!” shouted the lady to the man.
  
  

• Choose one sentence that has the same meaning to the root one:

  He last had his eyes tested ten months ago.