Cho hình chóp
có đáy
là hình vuông cạnh bằng
. Cạnh
vuông góc với đáy và
. Trên cạnh
lấy điểm
sao cho
. Biết rằng
. Tìm giá trị lớn nhất của thể tích khối chóp
.
![img1](https://cungthi.online/upload/questionbank3_20201220/eduquestion/201715088435795150/obj201715088435795150426754_images/obj201715088435795150426754_img1.png)
![img2](https://cungthi.online/upload/questionbank3_20201220/eduquestion/201715088435795150/obj201715088435795150426754_images/obj201715088435795150426754_img2.png)
![img3](https://cungthi.online/upload/questionbank3_20201220/eduquestion/201715088435795150/obj201715088435795150426754_images/obj201715088435795150426754_img3.png)
![img4](https://cungthi.online/upload/questionbank3_20201220/eduquestion/201715088435795150/obj201715088435795150426754_images/obj201715088435795150426754_img4.png)
![img5](https://cungthi.online/upload/questionbank3_20201220/eduquestion/201715088435795150/obj201715088435795150426754_images/obj201715088435795150426754_img5.png)
![img6](https://cungthi.online/upload/questionbank3_20201220/eduquestion/201715088435795150/obj201715088435795150426754_images/obj201715088435795150426754_img6.png)
![img7](https://cungthi.online/upload/questionbank3_20201220/eduquestion/201715088435795150/obj201715088435795150426754_images/obj201715088435795150426754_img7.png)
![img8](https://cungthi.online/upload/questionbank3_20201220/eduquestion/201715088435795150/obj201715088435795150426754_images/obj201715088435795150426754_img8.png)
![img9](https://cungthi.online/upload/questionbank3_20201220/eduquestion/201715088435795150/obj201715088435795150426754_images/obj201715088435795150426754_img9.png)
![img10](https://cungthi.online/upload/questionbank3_20201220/eduquestion/201715088435795150/obj201715088435795150426754_images/obj201715088435795150426754_img10.png)
A.
B.
C.
D.
Đáp án và lời giải
Đáp án:D
Lời giải:
Ta có ;
Xét hàm số .
nhận
.
.
Vậy đáp án đúng là: D.