Cho tứ diện đều cạnh . Gọi  lần lượt là trung điểm các cạnh . Tính khoảng cách giữa hai đường thẳng  và .        

Chia sẻ

Một số câu hỏi khác có thể bạn quan tâm.

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

  This problem is beyond my understanding.
  
  

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

  They have not finally decided on whether to adopt a new project.
  
  

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

  It is ten years since any bears have been caught in the area.
  
  

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

  The whole project would have fallen through without his support and hard work.
  
  

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

  No one can predict the future accurately.
  
  

•  Choose the best answer for the following sentence:

  If more and more people take part in the fight against illiteracy, illiteracy will soon __________.
   

•  Choose the best answer for the following sentence:

  _____________ was the effective way to help people in remote and mountainous
  areas to read and write?
   

• Choose a word that has different stress pattern:

  industrial                approximately             enormously            population

• Choose a word that has different stress pattern:

  separated              contraception               annually              gradually

• Choose the word that has the underlined part pronounced differently from the rest:

  contained            attracted                succeeded              implemented