Tìm giá trị cực tiểu
của hàm số
A. A:
![img1](https://cungthi.online/upload/questionbank3_20201220/eduquestion/2020440790783833316/obj2020440790783833316179979_images/obj2020440790783833316179979_img1.png)
B. B:
![img1](https://cungthi.online/upload/questionbank3_20201220/eduquestion/2020440790783833316/obj2020440790783833316734468_images/obj2020440790783833316734468_img1.png)
C. C:
![img1](https://cungthi.online/upload/questionbank3_20201220/eduquestion/2020440790783833316/obj2020440790783833316651083_images/obj2020440790783833316651083_img1.png)
D. D:
![img1](https://cungthi.online/upload/questionbank3_20201220/eduquestion/2020440790783833316/obj2020440790783833316143186_images/obj2020440790783833316143186_img1.png)
Đáp án và lời giải
Đáp án:D
Lời giải:
.
Hàm số cho là hàm bậc 3 có hệ số
nên ![img3](https://cungthi.online/upload/questionbank3_20201220/eduquestion/2020440790783833316/obj2020440790783833316645282_images/obj2020440790783833316645282_img3.png)
![img4](https://cungthi.online/upload/questionbank3_20201220/eduquestion/2020440790783833316/obj2020440790783833316645282_images/obj2020440790783833316645282_img4.png)
.
![img1](https://cungthi.online/upload/questionbank3_20201220/eduquestion/2020440790783833316/obj2020440790783833316645282_images/obj2020440790783833316645282_img1.png)
![img2](https://cungthi.online/upload/questionbank3_20201220/eduquestion/2020440790783833316/obj2020440790783833316645282_images/obj2020440790783833316645282_img2.png)
![img3](https://cungthi.online/upload/questionbank3_20201220/eduquestion/2020440790783833316/obj2020440790783833316645282_images/obj2020440790783833316645282_img3.png)
![img4](https://cungthi.online/upload/questionbank3_20201220/eduquestion/2020440790783833316/obj2020440790783833316645282_images/obj2020440790783833316645282_img4.png)
![img5](https://cungthi.online/upload/questionbank3_20201220/eduquestion/2020440790783833316/obj2020440790783833316645282_images/obj2020440790783833316645282_img5.png)