tìm biến trở Rx để Px max làm thế nào ạ ???

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Đáp án:

 Px max khi Rx=r khi đó Pmax

Giải thích các bước giải:

\begin{array}{l} P = {R_x}{I^2} = {R_x}{\frac{E}{{{R_x} + r}}^2} = \frac{{{E^2}}}{{{{(\sqrt {{R_x}}  + \frac{r}{{\sqrt {{R_x}} }})}^2}}}\\ {P_{\max }} \Rightarrow {(\sqrt {{R_x}}  + \frac{r}{{\sqrt {{R_x}} }})^2}_{\min } \end{array}

áp dụng cô si: \sqrt {{R_x}}  + \frac{r}{{\sqrt {{R_x}} }} \ge 2r

khi 

\begin{array}{l} \sqrt {{R_x}}  = \frac{r}{{\sqrt {{R_x}} }}\\ {R_x} = r \end{array}

suy ra: {P_{\max }} = \frac{{{E^2}}}{{4r}}

Đáp án:

tìm I qua Rx theo ẩn Rx


bạn biến đổi để trên tử là 1 hằng số, mẫu là biểu thức tính theo x
để Px max thì dưới mẫu min, dùng bất đẳng thức cosi để tìm

Giải thích các bước giải:

 

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Mọi người giúp mình bài này với!!!!!Uy tín 5 sao các bạn trả lời bài nhé!!!Cảm ơn các bạn!!! II. Fill in the blanks with a suitable word in the box. guardians sacred intricate dilapidated mainland chiseled bridge archaeologists MY SON SANCTUARY Hidden away in the tropical forest near the port city of Da Nang and the very popular World Heritage town of Hoi An is the Champa civilization’s (1) ____________________ valley of My Son, or “Beautifal Mountain”. I joined the full day package tour from Hoi An, which was quite very convenient as it included all transportation, ticket fee. lunch and guide. I arrived in My Son around 10 o’clock. After walking for a while, I found the complex of tourist facilities, and one of them is the performance hall. Our guide insisted us keeping going into the forest. Within few minutes, I started to see the complex of ancient Hindu temples made from brick At first, the (2) _______________________ state of the complex was quite shocking, and almost nothing was left to see. I decided to discover the site by myself and I started to be impressed by the amazing quality of brick carving details. The image of Hinduism (3) _________________________ and angels are truly beautiful and reminded me about Angkor in Cambodia. For me, My Son is the great evidence of how Southern Indian art expanded to Southeast Asia since ancient Cham people came from Java where Indian art flourished, and later expand to modern day Vietnam and later Cambodia and Thailand. The construction method of My Son is also very unique: Cham people built a whole block of bricks then burned them to make the whole brick block very solid and strong then (4) ____________________ into the temple. I walked around the complex many times to enjoy its (5) ___________________ motifs until the guide informed that there are more complex to see. I went to see another complex, this one is located on the hill and recently partial rebuilt by a group of Italian (6) ___________________, and they are planning to rebuild more, which is a very good news for My Son preservation. The rebuilt complex is very lovely and illustrates the original layout very well even though the new brick really contrasts with the old ones. After that, the guide took me back to the bus and back to Hoi An, it was exactly 3 hours inside My Son. Despite the bad state of preservation, I really enjoyed my visit to My Son, the place has exceeded my expectation and even small complex can clearly show its value as a (7) ___________________ of cultural exchange between India - Java and (8) _________________ Southeast Asia.

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