Cho đường thẳng
Để phép tịnh tiến theo
biến đường thẳng
thành chính nó thì
phải là véc tơ nào sau đây:
A.
![img1](https://cungthi.online/upload/questionbank3_20201220/eduquestion/2019001986851750448/obj2019001986851750448879533_images/obj2019001986851750448879533_img1.png)
B.
![img1](https://cungthi.online/upload/questionbank3_20201220/eduquestion/2019001986851750448/obj2019001986851750448653643_images/obj2019001986851750448653643_img1.png)
C.
![img1](https://cungthi.online/upload/questionbank3_20201220/eduquestion/2019001986851750448/obj2019001986851750448573192_images/obj2019001986851750448573192_img1.png)
D.
![img1](https://cungthi.online/upload/questionbank3_20201220/eduquestion/2019001986851750448/obj2019001986851750448811679_images/obj2019001986851750448811679_img1.png)
Đáp án và lời giải
Đáp án:C
Lời giải:Phép tịnh tiến theo
biến đường thẳng
thành chính nó khi và chỉ khi
hoặc
là một vectơ chỉ phương của
. Từ phương trình đường thẳng d, ta thấy
là một vectơ chỉ phương của
nên chọn đáp án C.
Vậy đáp án đúng là C.
![img1](https://cungthi.online/upload/questionbank3_20201220/eduquestion/2019001986851750448/obj2019001986851750448381298_images/obj2019001986851750448381298_img1.png)
![img2](https://cungthi.online/upload/questionbank3_20201220/eduquestion/2019001986851750448/obj2019001986851750448381298_images/obj2019001986851750448381298_img2.png)
![img3](https://cungthi.online/upload/questionbank3_20201220/eduquestion/2019001986851750448/obj2019001986851750448381298_images/obj2019001986851750448381298_img3.png)
![img4](https://cungthi.online/upload/questionbank3_20201220/eduquestion/2019001986851750448/obj2019001986851750448381298_images/obj2019001986851750448381298_img4.png)
![img5](https://cungthi.online/upload/questionbank3_20201220/eduquestion/2019001986851750448/obj2019001986851750448381298_images/obj2019001986851750448381298_img5.png)
![img6](https://cungthi.online/upload/questionbank3_20201220/eduquestion/2019001986851750448/obj2019001986851750448381298_images/obj2019001986851750448381298_img6.png)
![img7](https://cungthi.online/upload/questionbank3_20201220/eduquestion/2019001986851750448/obj2019001986851750448381298_images/obj2019001986851750448381298_img7.png)