K
Khách

Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.

3 tháng 5 2020

Từ gt => \(\hept{\begin{cases}\left(\frac{1}{\sqrt{2}}-\sqrt{x}\right)\left(\frac{1}{\sqrt{2}}-\sqrt{y}\right)\ge0\Leftrightarrow\sqrt{x}+\sqrt{y}\le\frac{\sqrt{2}}{2}+\sqrt{2}\sqrt{xy}\left(1\right)\\x\sqrt{x}\le x\cdot\frac{1}{\sqrt{2}};y\sqrt{y}\le y\cdot\frac{1}{\sqrt{2}}\Rightarrow x\sqrt{x}+y\sqrt{y}\le\frac{1}{\sqrt{2}}\left(x+y\right)\left(2\right)\end{cases}}\)

Lại có \(\hept{\begin{cases}\sqrt{xy}\le xy+\frac{1}{4}\\\sqrt{xy}\le\frac{x+y}{2}\end{cases}\Rightarrow\hept{\begin{cases}\frac{2\sqrt{2}}{3}\sqrt{xy}\le\frac{2\sqrt{2}}{3}\left(xy+\frac{1}{4}\right)\left(3\right)\\\frac{\sqrt{2}}{3}\sqrt{xy}\le\frac{\sqrt{2}}{6}\left(x+y\right)\left(4\right)\end{cases}}}\)

Từ (1)(2)(3)(4) ta có:\(x\sqrt{x}+y\sqrt{y}+\sqrt{x}+\sqrt{y}\le\frac{\sqrt{2}}{2}\left(x+y\right)+\frac{\sqrt{2}}{2}+\frac{2\sqrt{2}}{3}\left(xy+\frac{1}{4}\right)+\frac{\sqrt{2}}{6}\left(x+y\right)\)

\(\le\frac{2\sqrt{2}}{3}\left(1+x+y+xy\right)\)

=> \(VT=\frac{\sqrt{x}}{1+y}+\frac{\sqrt{y}}{1+x}=\frac{x\sqrt{x}+y\sqrt{y}+\sqrt{x}+\sqrt{y}}{1+x+y+xy}\le\frac{2\sqrt{2}}{3}\)

Dấu "=" xảy ra <=> x=y=\(\frac{1}{2}\)

8 tháng 12 2017

Đk : 1 < = x < = 5

B^2 = x-1+5-x + 2.\(\sqrt{\left(x-1\right)\left(5-x\right)}\)

Áp dụng bđt cosi thì :

B^2 >= 4 + x-1+5-x = 8

=>B < = 2\(\sqrt{2}\)

Vậy Max B = 2\(\sqrt{2}\)<=> x=1

k mk nha

8 tháng 12 2017

mk hc nghu lém mk giải ko dc nhưng cho mk xin nha mấy bn yêu mấy bn nh`

8 tháng 12 2017

x=5 y=15

8 tháng 12 2017

cái này là giải hpt rồi

9 tháng 12 2017

con lậy hỏi thế bố đứa nào trả lời được trừ Tuấn Anh

8 tháng 12 2017

The savory melt-in-your-mouth cheese; the sweet sauce; the fluffy yet crispy crust. When joined together on a pizza pan, the combination of flavors and textures is one that few of us can say "no" to. In fact, in an Eat This, Not That! survey of more than 10,000 readers, approximately 40 percent of respondents said that of all the guilty food pleasures on the planet, pizza is the one thing they could never, ever give up. Which we can't say was all too shocking to learn. Every day about 40 million people across America sit down to enjoy a slice. And while there are tons of reasons why our nation has such a high obesity rate, we can't help but wonder how large of a role all that pepperoni and cheese-stuffed crust are playing.

But, of course, there are two sides to every coin. Just as you can easily walk into a Dominos and order a large "Meatzza" (which clocks in at 370 calories, 17 grams of fat per slice, by the way), you can get a better-for-you 'za for a fraction of the calories. And according to the USDA, when your pizza contains the right mix of food groups, a pie can provide you with 37 percent of your bone-building calcium, 30 percent of the day's fiber, 35 percent of the day's protein, and over 50 percent of your recommended intake of lycopene (a cancer-attacking antioxidant found in tomatoes). The tricky part is identifying a pie that falls within these parameters. But that's where we come in!