Đặt $t=\tan x$
Hàm số trở thành $y=t^2-2t-1$
Parabol có đỉnh là $a=1>0$ và có đỉnh $x=-\dfrac{b}{2a}=1$
$\Rightarrow y=(1)^2-2.1=-2$
$\Rightarrow \min y=-2$
Dấu bằng xảy ra khi và chỉ khi
$\tan x=1\Rightarrow x=\dfrac{\pi} 4+k\pi (k\in \mathbb{Z})$
Rewrite the sentence using the given word in bold letters, keep the meaning unchanged. DO NOT CHANGE THE GIVEN WORD, USE FROM 2 TO 5 WORDS INCLUDING THE WORD GIVEN IN BRACKETS. 1. That bicycle was too expensive for me to buy. (enough) I ___________________________________________________ to buy that bicycle. 2. I'd prefer it if you didn't close the door. (mind) _____________________________________________________ closing the door? 3. Many people in the world speak English. (spoken) English _______________________________________ many people in the world. 4. "Do many tourists visit Phong Nha Cave every year, Hoa?" asked Tim. (if) Tim asked Hoa _______________________________ Phong Nha Cave every year.
Turn passive Lan washes her hair twice a week. What should we do now ? Hoa can’t do this work. We must do something when it’s too late. They used to drink beer for breakfast in England years ago - 4.Who wrote that story? -.................................................................................. 5.I don’t eat fish for lunch. -............................................................ 6. He donated a lot of money for the poor people. - .......................................................................... 7. Do they plant roses in the garden? - ............................................................................. 8. When does he usually do his homework.? - ……………………………………………………………………
CHỈ CẦN LÀM CÂU A THÔI KHÔNG CẦN VẼ HÌNH LUÔN
Mn làm giúp e với ạ Đúng = 5 sao + tlhn
câu 12 sửa lại là : hấp thụ hết 2,688 thành 2,24 nha mn hứa 5 vote cảm ơn 2 nick luôn Làm vài câu cũng đc ạ
Combine each of the following pairs of sentences into one sentence, using ADJ + ENOUGH 1. She can reach the top of the cupboard. She’s tall. 2. The ladder isn’t very long. It doesn’t reach the window. 3. He is strong. He can carry the suitcase.
V. Rewrite the following sentences using questions words + to-infinite. 1. Could you tell me when I should explain everything to our teacher? 2. Let us decide when we should start the project. 3. Could you tell me where I can find a good hotel? 4. We must find out what we are to do next. 5. A good dictionary tells you how you should pronounce the words.
giải giúp mình với ak :(( Mình cần gấp lắm
Cali: Doraemon Digi hay tradi đều đc á
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