Trong không gian
, cho tứ diện
có
và
thuộc trục
. Biết
và có hai điểm
thỏa mãn yêu cầu bài toán. Khi đó
bằng ?
![img1](https://cungthi.online/upload/questionbank3/eduquestion/2019451164352691138/obj2019451164352691138864635_images/obj2019451164352691138864635_img1.png)
![img2](https://cungthi.online/upload/questionbank3/eduquestion/2019451164352691138/obj2019451164352691138864635_images/obj2019451164352691138864635_img2.png)
![img3](https://cungthi.online/upload/questionbank3/eduquestion/2019451164352691138/obj2019451164352691138864635_images/obj2019451164352691138864635_img3.png)
![img4](https://cungthi.online/upload/questionbank3/eduquestion/2019451164352691138/obj2019451164352691138864635_images/obj2019451164352691138864635_img4.png)
![img5](https://cungthi.online/upload/questionbank3/eduquestion/2019451164352691138/obj2019451164352691138864635_images/obj2019451164352691138864635_img5.png)
![img6](https://cungthi.online/upload/questionbank3/eduquestion/2019451164352691138/obj2019451164352691138864635_images/obj2019451164352691138864635_img6.png)
![img7](https://cungthi.online/upload/questionbank3/eduquestion/2019451164352691138/obj2019451164352691138864635_images/obj2019451164352691138864635_img7.png)
![img8](https://cungthi.online/upload/questionbank3/eduquestion/2019451164352691138/obj2019451164352691138864635_images/obj2019451164352691138864635_img8.png)
A.
0.
B.
1.
C.
2.
D.
3.
Đáp án và lời giải
Đáp án:B
Lời giải:
Phân tích: Ta có:
.
Đáp án đúng là B.