$\Delta'$ không phải đạo hàm $\Delta$. $\Delta'$ là biệt thức sử dụng trong công thức nghiệm thu gọn, tiện lợi để dùng khi hệ số $b$ của PT bậc hai là số chẵn.
* Cho PT $ax^2+bx+c=0$ ($a\ne 0$)
Ta có $\Delta=b^2-4ac$
Nếu đặt $b'=\dfrac{b}{2}$ thì $\Delta'=b'^2-ac$
Đáp án:
`B`
Giải thích các bước giải:
`y=ax^3+bx^2+cx+d`
`toy'=3ax^2+2bx+c`
Nhìn vào đồ thị ta thấy đồ thị hàm số không có cực trị.
Nên có điều kiện: `{(a>0),(Δ'_(y')<0):}`
`<=>{(a>0),(b^2-3ac<0):}`
`toB`
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Task 4. Combine the two sentences using because. (Kết hợp 2 câu sử dụng because) 1. He didn't wear enough warm clothes. He's had a cold for two days. 2. It rained. I stayed home. 3. The lake is full of rubbish. They've decided to clean it up. 4. She works in that small town. She's lived in that small town for three years. 5. The neighbourhood is nice and quiet. They think they should move there.
a.x^2+4x-6=0 b.x^2+2x-3=0 Đề là tìm x mọi người giúp vs .....Tks
Các bạn giúp mình với nha Hứa vote cảm ơn hay nhất
chứng mình a//b hộ mik nhanh vơi snha
Bài14: học sinh lớp 6a khi học thể dục có thể xếp thành 4 hàng , 5 hàng, 8 hàng thì vừa đủ . Tính số học sinh của lớp biết lớp ko vượt quá 50 học sinh
-4/7-x=3/5-2x Giúp mình vs ạ 🥺 🥺🥺
Các bn làm giúp mình với xong mik cho 1 vote ⭐️⭐️⭐️⭐️⭐️
I. Choose the best answer A, B, C or D to complete the sentences: 1. A person who acts in a comedy is a __________ . A. reporter B. comedian C. film producer D. MC 2. ________ TV channels are there in Viet Nam? A. What B. When C. How many D. How often 3. __________ the Haunted Theatre is frightening, children love it. A. Because B. So C. But D. Although 4. Hoa likes _________ weather because she can go swimming. A. hot B. cold C. rainy D. wet 5. He __________ late for school. A. never is B. is never C. go never D. are never 6. _________ eat too much salt. It’s not good for you. A. Don’t B. Do C. Please D. Can’t 7. What’s your favourite_____________?-I like Tom and Jerry. A. subject B. game C. sport D. cartoon 8. If he __________my car, I’ll give him $5. A. washes B. wash C. will wash D. washing 9. I have studied English __________ 2000. A. in B. at C. since D. for 10. That is the _________ book I’ve ever read. A. most bored B. borest C. boring D. most boring II. Supply the corect tense or form of the verb in parentheses. 1. If it ( rain)…………………………….. tonight, I won’t go for a walk. 2. Duy is not reading now. He ( watch)…………………… a game of tennis on TV. 3. They ( never see)………………………………………. such a big flower. 4. The USA ( have)…………………………………. colour TV in 1953. 5. You shouldn’t ( eat)……………………………….. food in this canteen. II. Choose the correct word A, B, C or D for each gap to complete the following passage : I live in (1)________small village called Henfield. There (2)_______about 600 people here. I love the village because it is very quiet and life is slow (3)________easy. The village is always clean-people look (4)__________it with great care. The air is always clean, (5)_________ . It is much more friendly here than in a citybecause everyone knows everyone, and if someone has a problem, there are always people who can help. 1. A. a B. an C. the D. many 2. A. have B. is C. are D. be 3. A. but B. and C. or D. because 4. A. after B. for C. at D. with 5. A. also B. either C. so D. too
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