Cho
là các số thực dương. Biết
, tính
theo
và
.
![img1](https://cungthi.online/upload/questionbank3_20201220/eduquestion/20181307576716702309/obj20181307576716702309414364_images/obj20181307576716702309414364_img1.png)
![img2](https://cungthi.online/upload/questionbank3_20201220/eduquestion/20181307576716702309/obj20181307576716702309414364_images/obj20181307576716702309414364_img2.png)
![img3](https://cungthi.online/upload/questionbank3_20201220/eduquestion/20181307576716702309/obj20181307576716702309414364_images/obj20181307576716702309414364_img3.png)
![img4](https://cungthi.online/upload/questionbank3_20201220/eduquestion/20181307576716702309/obj20181307576716702309414364_images/obj20181307576716702309414364_img4.png)
![img5](https://cungthi.online/upload/questionbank3_20201220/eduquestion/20181307576716702309/obj20181307576716702309414364_images/obj20181307576716702309414364_img5.png)
A.
B.
C.
D.
Đáp án và lời giải
Đáp án:A
Lời giải:
Phân tích: Ta có:
Đáp án đúng là A