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xy+yz+zx=1 Hãy tìm min A=3(x^2+y^2)+z^2

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Lê Minh

6 tháng trước

Đáp án:

$A=3(x^2+y^2)+z^2=x^2+y^2+x^2+y^2+z^2+x^2+y^2$

ta có $x^2+y^2+z^2≥xy+yz+xz$

$(x-y)^2≥0$

$=>x^2+y^2≥-2xy$

$<=>x^2+y^2≥1-z^2$

$=>A≥x^2+y^2+1-2xy=(x-y)^2+1≥1$

dấu "=" xảy ra $<=> x=y=z$

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xy+yz+zx=1 Hãy tìm min A=3(x^2+y^2)+z^2

1 câu trả lời

Viết một đoạn văn hoàn chỉnh về lý do học tiếng Anh bằng cách đưa ra các manh mối ( ko chép mạng nhá)

việt nam dành độc lập vào năm nào

Choose the best answer.
I think you should buy ___ pack of mineral water instead. And you can also buy _ snacks such as potato crisps, 3 kilos of mandarins, 2 kilos of apples, 3 bunches of bananas, ____ cookies and soft candies.

Choose the best answer.
We should decorate our living room with _ orange banner. We also need ____ ribbons, balloons, party hats and costume.

Choose the best answer.
I think that ______ cauliflower is not enough for 3 people. Let’s buy one more.

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xy+yz+zx=1 Hãy tìm min A=3(x^2+y^2)+z^2

1 câu trả lời

Viết một đoạn văn hoàn chỉnh về lý do học tiếng Anh bằng cách đưa ra các manh mối ( ko chép mạng nhá)

việt nam dành độc lập vào năm nào

Choose the best answer.I think you should buy _____ pack of mineral water instead. And you can also buy _____ snacks such as potato crisps, 3 kilos of mandarins, 2 kilos of apples, 3 bunches of bananas, ______ cookies and soft candies.

Choose the best answer.We should decorate our living room with _____ orange banner. We also need ________ ribbons, balloons, party hats and costume.

Choose the best answer.I think that ______ cauliflower is not enough for 3 people. Let’s buy one more.

Đề thi - đề kiểm tra Xem thêm

Choose the best answer.
I think you should buy ___ pack of mineral water instead. And you can also buy _ snacks such as potato crisps, 3 kilos of mandarins, 2 kilos of apples, 3 bunches of bananas, ____ cookies and soft candies.

Choose the best answer.
We should decorate our living room with _ orange banner. We also need ____ ribbons, balloons, party hats and costume.

Choose the best answer.
I think that ______ cauliflower is not enough for 3 people. Let’s buy one more.