Giải hộ mình b3 ms ạ
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10 tháng 5 2022
c. x-1/x+2-1/x= 2/x^2 + 2x
d. 5+x/2 -3 > 1-2x/3
bạn giải hộ mình 2 câu này với ạ mình quên mất mấy bài kia mình làm được rồi
S
2 tháng 4 2022
Bài 3 :
a) nKMnO4 = 31,6/158 = 0,2 (mol)
PTHH : \(2KMnO_4-t^o->K_2MnO_4+MnO_2+O_2\)
Theo pthh : nO2 = 1/2 nKMnO4 = 0,1 (mol)
=> VO2 = 0,1.22,4 = 2,24 (l)
b) PTHH : \(2Mg+O_2-t^o->2MgO\)
Theo pthh : nMgO = 2nO2 = 0,2 (mol)
=> mMgO = 0,2.40 = 8 (g)
S
2 tháng 4 2022
Bài 5 :
a) nCu = 0,2 (mol)
nO2 = 0,2 (mol)
PTHH : \(2Cu+O_2-t^o->2CuO\)
Nhận thấy : \(\dfrac{nCu}{2}< nO_2\left(\dfrac{0,2}{2}< 0,2\right)\) => Spu,Cu hết, O2 dư
Theo pthh : nCuO = nCu = 0,2 (mol)
=> mCuO = 0,2.80 = 16 (g)
b) PTHH : \(CuO+H_2-t^o->Cu+H_2O\)
Theo pthh : nH2 = nCuO = 0,2 (mol)
=> VH2 = 0,2.22,4 = 4,48 (l)
M
giải hộ mình mấy bài này vs ạ !
2
6 tháng 5 2021
Bài 5 hình 1: (tự vẽ hình nhé bạn)
a) Xét ΔABD và ΔACB ta có:
\(\widehat{BAD}\)= \(\widehat{BAC}\) (góc chung)
\(\widehat{ABD}\)= \(\widehat{ACB}\) (gt)
=> ΔABD ~ ΔACB (g-g)
=> \(\dfrac{AB}{AC}\) = \(\dfrac{BD}{CB}\) = \(\dfrac{AD}{AB}\) (tsđd)
b) Ta có: \(\dfrac{AB}{AC}\) = \(\dfrac{AD}{AB}\) (cm a)
=> \(AB^2\) = AD.AC
=> \(2^2\) = AD.4
=> AD = 1 (cm)
Ta có: AC = AD + DC (D thuộc AC)
=> 4 = 1 + DC
=> DC = 3 (cm)
c) Xét ΔABH và ΔADE ta có:
\(\widehat{AHB}\) = \(\widehat{AED}\) (=\(90^0\))
\(\widehat{ADB}\) = \(\widehat{ABH}\) (ΔABD ~ ΔACB)
=> ΔABH ~ ΔADE
=> \(\dfrac{AB}{AD}\) = \(\dfrac{AH}{AE}\) = \(\dfrac{BH}{DE}\) (tsdd)
Ta có: \(\dfrac{S_{ABH}}{S_{ADE}}\) = \(\left(\dfrac{AB}{AD}\right)^2\)= \(\left(\dfrac{2}{1}\right)^2\)= 4
=> đpcm
6 tháng 5 2021
Tiếp bài 5 hình 2 (tự vẽ hình)
a) Xét ΔABC vuông tại A ta có:
\(BC^2\) = \(AB^2\) + \(AC^2\)
\(BC^2\) = \(21^2\) + \(28^2\)
BC = 35 (cm)
b) Xét ΔABC và ΔHBA ta có:
\(\widehat{BAC}\) = \(\widehat{AHB}\) ( =\(90^0\))
\(\widehat{ABC}\) = \(\widehat{ABH}\) (góc chung)
=> ΔABC ~ ΔHBA (g-g)
=> \(\dfrac{AB}{BH}\) = \(\dfrac{BC}{AB}\) (tsdd)
=> \(AB^2\) = BH.BC
=> \(21^2\) = 35.BH
=> BH = 12,6 (cm)
c) Xét ΔABC ta có:
BD là đường p/g (gt)
=> \(\dfrac{AD}{DC}\) = \(\dfrac{AB}{BC}\) (t/c đường p/g)
Xét ΔABH ta có:
BE là đường p/g (gt)
=> \(\dfrac{HE}{AE}\) = \(\dfrac{BH}{AB}\) (t/c đường p/g)
Mà: \(\dfrac{AB}{BC}\) = \(\dfrac{BH}{AB}\) (cm b)
=> đpcm
d) Ta có: \(\left\{{}\begin{matrix}\widehat{HBE}+\widehat{BEH}=90^0\\\widehat{ABD}+\widehat{ADB=90^0}\\\widehat{HBE}=\widehat{ABD}\end{matrix}\right.\)
=> \(\widehat{BEH}=\widehat{ADB}\)
Mà \(\widehat{BEH}=\widehat{AED}\) (2 góc dd)
Nên \(\widehat{ADB}=\widehat{AED}\)
=> đpcm
KY
15 tháng 7 2021
IV. Choose the best answer A, B, C, or D to complete each sentence.
1.Ms. Jones isn’t as nice …….. Ms. Smith.
A. as B. for C. like D. to
2. The rooms in Graduate Towers are……….. Patterson Hall.
A. larger than B. larger than that of
C. larger than those in D. larger than in
3. Although she is very popular, she is not……her sister.
A. pretty as B. as pretty
C. prettier than D. most pretty than
4. Tuition at an American university runs……. Six thousand dollars a semester.
A. so high as B. as high to
C. as high as D. as high than
5. Everyone looks much………. today than they did yesterday.
A. happy B. happily C. more happily D. happier
6. Mr. Brown receives a …….. salary than anyone else in the company.
A. big B. more bigger C. bigger D. the bigger
7. The Boeing 747 is twice…….. the Boeing 707.
A. bigger than B. as bigger as
C. as big as D. more bigger than
8. “Do you know that beautiful lady over there?” “ Yes, that’s Wanida. She’s…………. in her group.”
A. more beautiful than any girl B. more beautiful than any other girl
C. so beautiful as other girl D. beautiful more than another girl
9. My young brother grew very quickly and soon he was……..my mother.
A. more big than B. so big than
C. as big as D. too big than
10.He is not……. tall as his father.
A. the B. as C. than D. more
11. John’s grade……. than his sister’s.
A. higher B. more high C. more higher D. the highest
12. She speaks English as……….as her friend does.
A. good B. well C. better D. the best
13. He works more ………..than I.
A. slow B. slowly C. most slowly D. slowest
14. My book is as……….as yours.
A. good B. well C. better D. the best
15. I love you……….than I can say.
A. much B. many C. more D. the most
16. It’s………….to go by bus than by car.
A. cheaper B. cheapest C. more cheap D. more cheaper
17. This hotel must be………..than the small one next door.
A. expensive B. more expensive
C. the most expensive D. the more expensive
17. An orange is ……… than a plum.
A. more large B. more larger C. larger D. the largest
18. This river is……… than that river.
A. narrow B. narrowest C. narrower D. most narrow
19. The test is not………difficult……….it was last month.
A. as/ as B. so/ as C. more/ as D. A and B
20. Peter usually drives………..Mary.
A. more fast B. more fast than C. faster than D. B and C
21. The hotel was…….any one we had stayed at before.
A. more expensive than B. more expensive as
C. most expensive than D. better expensive than
22. A: It’s a long way from Britian, isn’t it?
B: Yes, but it isn’t as……….as Hong Kong.
A. far B. farther C. farthest D. further
23. The larger the apartment, the................... the rent.
A. expensive B. more expensive C. expensively D. most expensive
24. She plays the piano …………… as she sings.
A. as beautifully B. more beautifully
C. as beautiful D. the most beautifully
25. The streets are getting more and …………… these days.
A. crowded B. less crowded C. more crowded D. most crowded
26. The larger the city, …………… the crime rate.
A. highest B. higher C. the highest D. the higher
27. You must explain your problems …………....
A. as clear as you can B. as clearly as you can
C. as clear than you are D. as clearly as you are
28. Her grandfather’s illness was…………………..we thought at first.
A. more seriously as B. as seriously as C. more serious than D. as serious than
29. My brother was feeling tired last night, so he went to bed…………..usual.
A. more early than B. as early as C more earlier as D. earlier than
DT
Đỗ Thanh Hải
CTVVIP
15 tháng 7 2021
IV. Choose the best answer A, B, C, or D to complete each sentence.
1.Ms. Jones isn’t as nice …….. Ms. Smith.
A. as B. for C. like D. to
2. The rooms in Graduate Towers are……….. Patterson Hall.
A. larger than B. larger than that of
C. larger than those in D. larger than in
3. Although she is very popular, she is not……her sister.
A. pretty as B. as pretty
C. prettier than D. most pretty than
4. Tuition at an American university runs……. Six thousand dollars a semester.
A. so high as B. as high to
C. as high as D. as high than
5. Everyone looks much………. today than they did yesterday.
A. happy B. happily C. more happily D. happier
6. Mr. Brown receives a …….. salary than anyone else in the company.
A. big B. more bigger C. bigger D. the bigger
7. The Boeing 747 is twice…….. the Boeing 707.
A. bigger than B. as bigger as
C. as big as D. more bigger than
8. “Do you know that beautiful lady over there?” “ Yes, that’s Wanida. She’s…………. in her group.”
A. more beautiful than any girl B. more beautiful than any other girl
C. so beautiful as other girl D. beautiful more than another girl
9. My young brother grew very quickly and soon he was……..my mother.
A. more big than B. so big than
C. as big as D. too big than
10.He is not……. tall as his father.
A. the B. as C. than D. more
11. John’s grade……. than his sister’s.
A. higher B. more high C. more higher D. the highest
12. She speaks English as……….as her friend does.
A. good B. well C. better D. the best
13. He works more ………..than I.
A. slow B. slowly C. most slowly D. slowest
14. My book is as……….as yours.
A. good B. well C. better D. the best
15. I love you……….than I can say.
A. much B. many C. more D. the most
16. It’s………….to go by bus than by car.
A. cheaper B. cheapest C. more cheap D. more cheaper
17. This hotel must be………..than the small one next door.
A. expensive B. more expensive
C. the most expensive D. the more expensive
17. An orange is ……… than a plum.
A. more large B. more larger C. larger D. the largest
18. This river is……… than that river.
A. narrow B. narrowest C. narrower D. most narrow
19. The test is not………difficult……….it was last month.
A. as/ as B. so/ as C. more/ as D. A and B
20. Peter usually drives………..Mary.
A. more fast B. more fast than C. faster than D. B and C
21. The hotel was…….any one we had stayed at before.
A. more expensive than B. more expensive as
C. most expensive than D. better expensive than
22. A: It’s a long way from Britian, isn’t it?
B: Yes, but it isn’t as……….as Hong Kong.
A. far B. farther C. farthest D. further
23. The larger the apartment, the................... the rent.
A. expensive B. more expensive C. expensively D. most expensive
24. She plays the piano …………… as she sings.
A. as beautifully B. more beautifully
C. as beautiful D. the most beautifully
25. The streets are getting more and …………… these days.
A. crowded B. less crowded C. more crowded D. most crowded
26. The larger the city, …………… the crime rate.
A. highest B. higher C. the highest D. the higher
27. You must explain your problems …………....
A. as clear as you can B. as clearly as you can
C. as clear than you are D. as clearly as you are
28. Her grandfather’s illness was…………………..we thought at first.
A. more seriously as B. as seriously as C. more serious than D. as serious than
29. My brother was feeling tired last night, so he went to bed…………..usual.
A. more early than B. as early as C more earlier as D. earlier than
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
giải hộ mình vs ạ mình cần gấp ạ
a.
Do \(-1\le sin2x\le1\) nên pt có nghiệm khi:
\(-1\le\dfrac{m+3}{2m-1}\le1\) \(\Leftrightarrow\left\{{}\begin{matrix}\dfrac{m+3}{2m-1}+1\ge0\\\dfrac{m+3}{2m-1}-1\le0\end{matrix}\right.\)
\(\Leftrightarrow\left\{{}\begin{matrix}\dfrac{3m+2}{2m-1}\ge0\\\dfrac{4-m}{2m-1}\le0\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}m\le-\dfrac{2}{3}\\m\ge4\end{matrix}\right.\)
-1 ở đâu vậy ạ