Giải phương trình bằng phương pháp đưa về phương trình tích:
1. cosx + cos2x + cos3x
= -1 2. sin^6x + cos^6x
= sin^4x + cos^4x
Đáp án:
Giải thích các bước giải:
Sin^6x+Cos^6x= 1-3/4 sin²2x
⇔ 2.(1-3/4 sin²2x)-1/2sin2x=0
đặt Sin2x= t
⇔ 2.(1-3/4t²)-1/2t=0
⇔-3/4t²-1/2t+2=0
⇔ t=1
t= -4/3 (loại)
Với t=1⇒ x= pi/4 +kpi
Giải phương trình ạ , giúp tôi với đag cần gấp
Complete the sentences with these words/phrases. as long as if only in case on condition that unless when wish 1 I wouldn’t move to the country Answer I had to. I much prefer living in the city. 2 Answer I didn’t have to share a bedroom with my younger sister. She’s so annoying! 3 I Answer I lived near the sea. I’d walk on the beach every day. 4 It’s really annoying Answer there are traffic jams. It takes twice as long to get to school. 5 My dad’s company will pay for us to move to the city Answer he stays with the company for three years. 6 Can you give me your mobile number Answer I need to phone you? 7 My mum is happy to move to the city Answer the house has a big garden.
Giúp mình với mình đang cần gấp để nộp bài cho cô bạn làm được cả 2 bài vote cho 5 sao
Bài 1. Find and correct the mistake 1 : I often gets up early to catch the bus to go to scholl 2: They doesn't own sa house .They still have to rent one to live 3: Bruce and Tim doesn't go swimming in the lake Bài 2 : choose the best answer 1: I ( catch /catcher) robbers 2: we ( live / lives) in the country
Làm một bài văn với đề bài:Tôi không phải là cô chủ, cậu chủ tốt.
16. That car was too expensive for me to buy. → That car was so → So → It was so → It was such → Such Mấy cao nhân gíup tui với ạ, hứa cho 5* ạ. Cảm ơn trc cao nhân ạ
Rewrite the sentences: 1. Despite knowing the area well , I got lost . -> Although ................. 2. They made the children do thi. -> The children…………………………. 3.I haven’t enjoyed myself so much for years.->It’s years since I enjoyed myself so much. 4.He’s very thin, that’s why he feels the cold so much. ->If he ........................... 5.She first moved into that house in 1989. She has………………………… 6.They haven't seen their uncle for ten years. It's……………………….. 7. “Why don’t we go and have a look at the cathedral?”He suggested......................................... 8.Please let me open the window. Would you mind ..........................................? 9.I went swimming every Thursday when I was at school. =>I used……………. 10. Mary was sick. She didn’t leave the meeting until it ended. =>Despite……….
tính (x^2-3) . ( x^4+3x^2+9) giúp e vs ạ
giúp em 2 bài này với ạ mng :(((
Ex 4. Write the correct form of the verb in brackets. 1. _________________(you/eat) fried chicken last night? 2. He ________________(put) on a lot of weight recently. 3. I often ___________(drink) coca cola when I was a child. 4. Joane _____________(wash) her face regularly to prevent spots. 5. I think he ______________(not pass) the exam. He hasn’t studied at all. 6. She _____________(have) a sore throat, and she __________(cough) terribly now. 7. You should try ____________(exercise) a couple times aweek. 8. He keeps ____________(sneeze), so I think he’s got a cold. 9. What ____________(you/ do) tomorrow evening? 10. My mother doesn’t like___________(eat) fast food. Ex 5. Supply the correct form of the verb in brackets. 1. The Japanese eat____________, so they have high life expectancy. (health) 2. Drinking unclean water can cause____________. (sick) 3. My uncle is a__________. He doesn’t eat meat or fish. (vegetable) 4. __________________can increase the risk of heart disease and diabetes (obese) 5. I’m _________to shellfish, so I can’t eat lobster and shrimp. (allerfy) 6. I got ____________during my beach vacation. (sunburn) 7. Lack of vitamin E can cause skin diseases and ______________(tired) 8. The symptoms of the disease include fever and ______________. (head)
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