Trong không gian với hệ toạ độ
, cho hai mặt phẳng
:
;
:
. Giao tuyến của hai mặt phẳng
,
là một đường thẳng đi qua điểm nào dưới đây?
A.
![img1](https://cungthi.online/upload/questionbank3_20201220/eduquestion/2019030483042946526/obj2019030483042946526513807_images/obj2019030483042946526513807_img1.png)
B.
![img1](https://cungthi.online/upload/questionbank3_20201220/eduquestion/2019030483042946526/obj2019030483042946526433356_images/obj2019030483042946526433356_img1.png)
C.
![img1](https://cungthi.online/upload/questionbank3_20201220/eduquestion/2019030483042946526/obj2019030483042946526430421_images/obj2019030483042946526430421_img1.png)
D.
![img1](https://cungthi.online/upload/questionbank3_20201220/eduquestion/2019030483042946526/obj2019030483042946526718366_images/obj2019030483042946526718366_img1.png)
Đáp án và lời giải
Đáp án:A
Lời giải:Cách 1:
mp
có vectơ pháp tuyến là
.
mp
có vectơ pháp tuyến là
.
Gọi
. Ta có
qua điểm
và có vectơ chỉ phương là
. Phương trình đường thẳng
:
.
Dễ thấy
.
Cách 2:
Giả sử giao tuyến của hai mặt phẳng
,
là một đường thẳng đi qua điểm
.
Khi đó:
. Kiểm tra các điểm
,
,
,
. Ta thấy chỉ có điểm
cùng thuộc hai mặt phẳng
,
. Vậy
là điểm cần tìm.
Vậy đáp án đúng là A.
![img1](https://cungthi.online/upload/questionbank3_20201220/eduquestion/2019030483042946526/obj2019030483042946526510941_images/obj2019030483042946526510941_img1.png)
![img2](https://cungthi.online/upload/questionbank3_20201220/eduquestion/2019030483042946526/obj2019030483042946526510941_images/obj2019030483042946526510941_img2.png)
![img3](https://cungthi.online/upload/questionbank3_20201220/eduquestion/2019030483042946526/obj2019030483042946526510941_images/obj2019030483042946526510941_img3.png)
![img4](https://cungthi.online/upload/questionbank3_20201220/eduquestion/2019030483042946526/obj2019030483042946526510941_images/obj2019030483042946526510941_img4.png)
![img5](https://cungthi.online/upload/questionbank3_20201220/eduquestion/2019030483042946526/obj2019030483042946526510941_images/obj2019030483042946526510941_img5.png)
![img6](https://cungthi.online/upload/questionbank3_20201220/eduquestion/2019030483042946526/obj2019030483042946526510941_images/obj2019030483042946526510941_img6.png)
![img7](https://cungthi.online/upload/questionbank3_20201220/eduquestion/2019030483042946526/obj2019030483042946526510941_images/obj2019030483042946526510941_img7.png)
![img8](https://cungthi.online/upload/questionbank3_20201220/eduquestion/2019030483042946526/obj2019030483042946526510941_images/obj2019030483042946526510941_img8.png)
![img9](https://cungthi.online/upload/questionbank3_20201220/eduquestion/2019030483042946526/obj2019030483042946526510941_images/obj2019030483042946526510941_img9.png)
![img10](https://cungthi.online/upload/questionbank3_20201220/eduquestion/2019030483042946526/obj2019030483042946526510941_images/obj2019030483042946526510941_img10.png)
![img11](https://cungthi.online/upload/questionbank3_20201220/eduquestion/2019030483042946526/obj2019030483042946526510941_images/obj2019030483042946526510941_img11.png)
![img12](https://cungthi.online/upload/questionbank3_20201220/eduquestion/2019030483042946526/obj2019030483042946526510941_images/obj2019030483042946526510941_img12.png)
![img13](https://cungthi.online/upload/questionbank3_20201220/eduquestion/2019030483042946526/obj2019030483042946526510941_images/obj2019030483042946526510941_img13.png)
![img14](https://cungthi.online/upload/questionbank3_20201220/eduquestion/2019030483042946526/obj2019030483042946526510941_images/obj2019030483042946526510941_img14.png)
![img15](https://cungthi.online/upload/questionbank3_20201220/eduquestion/2019030483042946526/obj2019030483042946526510941_images/obj2019030483042946526510941_img15.png)
![img16](https://cungthi.online/upload/questionbank3_20201220/eduquestion/2019030483042946526/obj2019030483042946526510941_images/obj2019030483042946526510941_img16.png)
![img17](https://cungthi.online/upload/questionbank3_20201220/eduquestion/2019030483042946526/obj2019030483042946526510941_images/obj2019030483042946526510941_img17.png)
![img18](https://cungthi.online/upload/questionbank3_20201220/eduquestion/2019030483042946526/obj2019030483042946526510941_images/obj2019030483042946526510941_img18.png)
![img19](https://cungthi.online/upload/questionbank3_20201220/eduquestion/2019030483042946526/obj2019030483042946526510941_images/obj2019030483042946526510941_img19.png)
![img20](https://cungthi.online/upload/questionbank3_20201220/eduquestion/2019030483042946526/obj2019030483042946526510941_images/obj2019030483042946526510941_img20.png)
![img21](https://cungthi.online/upload/questionbank3_20201220/eduquestion/2019030483042946526/obj2019030483042946526510941_images/obj2019030483042946526510941_img21.png)
![img22](https://cungthi.online/upload/questionbank3_20201220/eduquestion/2019030483042946526/obj2019030483042946526510941_images/obj2019030483042946526510941_img22.png)
![img23](https://cungthi.online/upload/questionbank3_20201220/eduquestion/2019030483042946526/obj2019030483042946526510941_images/obj2019030483042946526510941_img23.png)