Giải hộ mình với ạ
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AM
1
1 tháng 11 2021
Câu 1:
TXĐ:D=R
\(f\left(-x\right)=2\cdot\left(-x\right)^4-3\cdot\left(-x\right)^2+1\)
\(=2x^4-3x^2+1=f\left(x\right)\)
=>f(x) là hàm số chẵn
18 tháng 2 2021
1) Vì x=25 thỏa mãn ĐKXĐ nên Thay x=25 vào biểu thức \(A=\dfrac{\sqrt{x}-2}{x+1}\), ta được:
\(A=\dfrac{\sqrt{25}-2}{25+1}=\dfrac{5-2}{25+1}=\dfrac{3}{26}\)
Vậy: Khi x=25 thì \(A=\dfrac{3}{26}\)
2) Ta có: \(B=\dfrac{\sqrt{x}-3}{\sqrt{x}+1}+\dfrac{2x+8\sqrt{x}-6}{x-\sqrt{x}-2}\)
\(=\dfrac{\left(\sqrt{x}-3\right)\left(\sqrt{x}-2\right)}{\left(\sqrt{x}-2\right)\left(\sqrt{x}+1\right)}+\dfrac{2x+8\sqrt{x}-6}{\left(\sqrt{x}-2\right)\left(\sqrt{x}+1\right)}\)
\(=\dfrac{x-5\sqrt{x}+6+2x+8\sqrt{x}-6}{\left(\sqrt{x}-2\right)\left(\sqrt{x}+1\right)}\)
\(=\dfrac{3x+3\sqrt{x}}{\left(\sqrt{x}-2\right)\left(\sqrt{x}+1\right)}\)
\(=\dfrac{3\sqrt{x}\left(\sqrt{x}+1\right)}{\left(\sqrt{x}-2\right)\left(\sqrt{x}+1\right)}\)
\(=\dfrac{3\sqrt{x}}{\sqrt{x}-2}\)
22 tháng 2 2021
a) Phương trình hoành độ giao điểm là:
\(x^2=\left(m+2\right)x-2m\)
\(\Leftrightarrow x^2-\left(m+2\right)x+2m=0\)
\(\Delta=\left(m+2\right)^2-8m=m^2+4m+4-8m=m^2-4m+4=\left(m-2\right)^2\)
Để (d) và (P) cắt nhau tại hai điểm phân biệt thì \(\Delta>0\)
\(\Leftrightarrow\left(m-2\right)^2>0\)
mà \(\left(m-2\right)^2\ge0\)
nên \(m-2\ne0\)
hay \(m\ne2\)
Vậy: Để (d) và (P) cắt nhau tại hai điểm phân biệt thì \(m\ne2\)
Các bạn giải giúp mình với ạ, phần a ghi chi tiết bước giải hộ mình nhé. Mình cám ơn ạ! (Mai mình nộp rồi nên nhanh giúp mình ạ T.T)
13 tháng 1 2022
a: ĐKXĐ: \(x\notin\left\{10;-10;\sqrt{10};-\sqrt{10}\right\}\)
b: \(A=\dfrac{5x^3+50x+2x^2+20+5x^3-50x-2x^2+20}{\left(x^2-10\right)\left(x^2+10\right)}\cdot\dfrac{x^2-100}{x^2+4}\)
\(=\dfrac{10x^3+40}{\left(x^2-10\right)\left(x^2+10\right)}\cdot\dfrac{x^2-100}{x^2+4}\)
TL
0
30 tháng 4 2021
Mình làm giúp bạn phần II thôi nhé phần một có trong sgk đấy
12 tháng 6 2021
bài 46:
a, \(x+y=2=>\left(x+y\right)^2=4\)\(=>x^2+y^2+2xy=4=>10+2xy=4\)
\(=>xy=\dfrac{4-10}{2}=-3\)
\(x^3+y^3=x^3+3x^2y+3xy^2+y^3-3xy\left(x+y\right)\)
\(=\left(x+y\right)^3\)\(-3xy\left(x+y\right)=2^3-3.\left(-3\right).2=26\)
\(b,\) \(x+y=a=>x^2+2xy+y^2=a^2\)
\(=>xy=\dfrac{a^2-b}{2}\)
có: \(x^3+y^3=\left(x+y\right)^3-3xy\left(x+y\right)=a^3-3\left(\dfrac{a^2-b}{2}\right)a\)
\(=a^3-\dfrac{3a^3-3ab}{2}\)
BG
12 tháng 6 2021
a) Gọi n = a2 + b2
Suy ra 2n = 2a2 + 2b2 = a2 + 2ab + b2 + a2 - 2ab + b2
= (a + b)2 + (a - b)2
b) theo đề bài ta có: 2n = a2 + b2
=> n= a2/2 + b2/2 => (a2/4 + 2.a/2.b/2 + b2/4) + (a2/4 + 2a/2.b/2 + b2/4
= (a + b)2/2 + (a - b)2/2
c) n2 = (a2 + b2)2 = a4 + 2a2.b2 + b4 = a4 - 2a2.b2 + b4 + 4a2.b2
= (a2 - b2)2 + (2ab)2
d) m.n = (a2 + b2)(c2 + d2) = a2.c2 + a2. d2 + b2.c2 + b2.d22
= (a2.c2 + 2a2.b2.c2.d2 + b2.d2) + (a2.d2 - 2a2.b2.c2.d2 + b2.c2)
= (ac +ab)2 + (ad + bc)2
1. If Jane wore a coat, she wouldn’t feel cold.
2. If it hadn’t rained heavily, we wouldn’t have stayed at home.
3. If we didn’t finish the work late, we could have lunch.
4. If she hadn’t won the scholarship, I wouldn’t have given her a gift.
5. If they didn’t have fat tyrpe, they wouldn’t arrive late.
6. If John didn’t eat so many chips, he wouldn’t be fat.
7. If I hadn’t been so busy, I could have arrived to you.
8. If the English teacher hadn’t spoken too fats, we could have understood her.
9. If she ate breakfast, she wouldn’t feel hungry in class.
10. If I hadn’t been sick, I would have gone to school.
11. If I had thought carefully, I wouldn’t make that terrible mistake.
12. If his friends hadn’t been late, they wouldn’t have missed the train.
13. If the motor weren’t expensive, I could afford it.
14. If you didn’t drink too much coffee, you could sleep.
15. If the car in front hadn’t stopped so sudden;y, I wouldn’t have crashed into its back.
16. If I had eaten breakfast several hours ago, I wouldn’t be hungry now.
1. If he had prepared for the interview, he would have got the job.
2. If we hadn’t run out of money, we wouldn’t have come home from our holiday early.
3. If I hadn’t gone to bed late, I wouldn’t have felt tired in the morning.
4. If the fire brigade hadn’t come immediately, the house would have burnt down.
5. If we hadn’t left the party late, we could have got a bus.
6. If I had known how difficult the job was, I wouldn’t have taken it.
7. If the woman hadn’t received immediate medical attention, she would have died.
8. If Ann had passed the entrance examination, she would have been admitted to the university.
9. If I knew the answer, I could tell you.
10. If he could park near his office, he would come by car.
11. If we didn’t have three children, we would take a year off and travel around the world.
12. If Jim didn’t work very hard, he would have time to spend with his family.
13. If I didn’t have a headache, I could go swimming.