Gọi
là nghiệm dương nhỏ nhất của
Mệnh đề nào sau đây là đúng?
A.
![img1](https://cungthi.online/upload/questionbank3/eduquestion/20191326846421554621/obj20191326846421554621827273_images/obj20191326846421554621827273_img1.png)
B.
![img1](https://cungthi.online/upload/questionbank3/eduquestion/20191326846421554621/obj20191326846421554621350369_images/obj20191326846421554621350369_img1.png)
C.
![img1](https://cungthi.online/upload/questionbank3/eduquestion/20191326846421554621/obj20191326846421554621762353_images/obj20191326846421554621762353_img1.png)
D.
![img1](https://cungthi.online/upload/questionbank3/eduquestion/20191326846421554621/obj20191326846421554621855400_images/obj20191326846421554621855400_img1.png)
Đáp án và lời giải
Đáp án:B
Lời giải:Phương trình
.
.
Đặt
Phương trình trở thành
.
=
.
Suy ra nghiệm dương nhỏ nhất của phương trình là
Vậy đáp án đúng là B.
![img1](https://cungthi.online/upload/questionbank3/eduquestion/20191326846421554621/obj20191326846421554621743957_images/obj20191326846421554621743957_img1.png)
![img2](https://cungthi.online/upload/questionbank3/eduquestion/20191326846421554621/obj20191326846421554621743957_images/obj20191326846421554621743957_img2.png)
![img3](https://cungthi.online/upload/questionbank3/eduquestion/20191326846421554621/obj20191326846421554621743957_images/obj20191326846421554621743957_img3.png)
![img4](https://cungthi.online/upload/questionbank3/eduquestion/20191326846421554621/obj20191326846421554621743957_images/obj20191326846421554621743957_img4.png)
![img5](https://cungthi.online/upload/questionbank3/eduquestion/20191326846421554621/obj20191326846421554621743957_images/obj20191326846421554621743957_img5.png)
![img6](https://cungthi.online/upload/questionbank3/eduquestion/20191326846421554621/obj20191326846421554621743957_images/obj20191326846421554621743957_img6.png)
![img7](https://cungthi.online/upload/questionbank3/eduquestion/20191326846421554621/obj20191326846421554621743957_images/obj20191326846421554621743957_img7.png)
![img8](https://cungthi.online/upload/questionbank3/eduquestion/20191326846421554621/obj20191326846421554621743957_images/obj20191326846421554621743957_img8.png)