Mọi người giải hộ em được không, em bí mấy bữa nay rồi.
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DT
1
Những câu hỏi liên quan
HT
2
9 tháng 9 2021
a,\(\Rightarrow\)R4 nt R5 nt {(R1 nt R3)//R2)}(goi R3=x(\(\Omega\))
\(\Rightarrow Rtd=R4+R5+\dfrac{R2\left(R1+x\right)}{R2+R1+x}=\dfrac{U}{Ia1}=\dfrac{6}{0,5}=12\Omega\)
\(\Rightarrow3+6+\dfrac{4\left(6+x\right)}{4+6+x}=12\Rightarrow x=R3=6\Omega\)
b, \(\Rightarrow\)R5 nt {R3 // {R2 nt (R1//R4)}} lay R3=6(om)
\(\Rightarrow Ia1=\dfrac{U}{Rtd}=\dfrac{6}{R5+\dfrac{R3\left\{R2+\dfrac{R1R4}{R1+R4}\right\}}{R3+R2+\dfrac{R1R4}{R1+R4}}}=\dfrac{6}{9}=\dfrac{2}{3}A\)
\(\Rightarrow Ia1=Ia2+I1\Rightarrow Ia2=Ia1-I1=\dfrac{2}{3}-I1\)
\(\Rightarrow U124=U-U5=6-Ia1.R5=2V\Rightarrow I14=\dfrac{U124}{R124}=\dfrac{2}{R2+\dfrac{R1R4}{R1+R4}}=\dfrac{1}{3}A\Rightarrow U14=U1=I14.R14=\dfrac{2}{3}V\Rightarrow I1=\dfrac{U1}{R1}=\dfrac{1}{9}A\Rightarrow Ia2=\dfrac{2}{3}-\dfrac{1}{9}=\dfrac{5}{9}A\)
12 tháng 7 2017
nối 1 điểm bất kì với n-1 điểm còn lại ta đc n-1 đường thẳng=>số đường thẳng vẽ đc là:n.(n-1)
mà mỗi đường thẳng đc nhắc lại 2 lần
=>số đường thẳng vẽ đc trên thực tế là:
\(\frac{n\left(n-1\right)}{2}\)=\(\frac{2017.2016}{2}=2033136\)(đường thẳng)
vậy.......
AL
12 tháng 7 2017
Cứ 1 điểm ta lại tạo được với 2016 điểm còn lại 2016 đường thẳng.
=>Số đường thẳng có là:
2016 x 2017=4066272(đường thẳng)
Nhưng thực chất mỗi đường thẳng được nhắc lại 2 lần nên ta có:
Số đường thẳng thật sự là:
4066272 :2=2033136(đường thẳng)
Vật cho 2017 điểm trong đó không có 3 điểm nào thẳng hàng,ta vẽ được 2033136 đường thẳng
Học giỏi ^^
H
1 tháng 11 2023
Bài `13`
\(a,\sqrt{27}+\sqrt{48}-\sqrt{108}-\sqrt{12}\\ =\sqrt{9\cdot3}+\sqrt{16\cdot3}-\sqrt{36\cdot3}-\sqrt{4\cdot3}\\ =3\sqrt{3}+4\sqrt{3}-6\sqrt{3}-2\sqrt{3}\\ =\left(3+4-6-2\right)\sqrt{3}\\ =-\sqrt{3}\\ b,\left(\sqrt{28}+\sqrt{12}-\sqrt{7}\right)\cdot\sqrt{7}+\sqrt{84}\\ =\left(\sqrt{4\cdot7}+\sqrt{4\cdot3}-\sqrt{7}\right)\cdot\sqrt{7}+\sqrt{4\cdot21}\\ =\left(2\sqrt{7}+2\sqrt{3}-\sqrt{7}\right)\cdot\sqrt{7}+2\sqrt{21}\\ =2\cdot7+2\sqrt{21}-7+2\sqrt{21}\\ =14+2\sqrt{21}-7+2\sqrt{21}\\ =7+4\sqrt{21}\)
LP
18 tháng 5 2022
.... in my family has never left home for 2 days.
N
5 tháng 11 2021
NỐI TIẾP:
\(\left\{{}\begin{matrix}R=R1+R2\left(\Omega\right)\\I=I1=I2\left(A\right)\\U=U1+U2\left(V\right)\end{matrix}\right.\)
SONG SONG:
\(\left\{{}\begin{matrix}R=\dfrac{R1.R2}{R1+R2}\Omega\\I=I1+I2\left(A\right)\\U=U1=U2\left(V\right)\end{matrix}\right.\)
I: cường độ dòng điện (A)
U: Hiệu điện thế (V)
R: điện trở (\(\Omega\))
Refer
1. Paul was driving a car when he heard this news.
2. Tom always comes late for his classes.
3. I locked the door and went to the shop.
4. Pam is jogging in the nearest park at the moment.
5. Helen will call her granny tomorrow morning.
6. They have already bought tickets for the performance.
7. My brother had cleaned the room before I came home.
8. Where have you been recently?
9. Who is playing the computer games now?
10. Where were you going when I saw you yesterday?
11. When will Tim write his report for the future conference?
12. Why did Andrew miss his lectures yesterday?
13. When do you usually have your lunch?
14. What had Ben written on the blackboard when Nick saw him?
15. I do not like to go to the museums at all.
16. He will not help you because he will be very busy tomorrow.
17. Sam did not answer my questions yesterday.
18. John has not written this difficult grammar test yet.
19. Mona had not translated the text when I came home.
20. Mary is not playing with her dolls at the moment.
21. The boys were not playing football at 3 o’clock yesterday.
22. I always watch films on TV.
23. Bill often draws wild animals in his copy-books.
24. Nick will bring his parrot to school tomorrow.
25. Jessica has already spent all her money on souvenirs.
26. We went to the amusement park yesterday.
27. I am not cooking dinner at the moment.
28. The boys were talking when I saw them yesterday.
29. My mum had laid the table before we came home.
30. The girls sang a wonderful song at the concert yesterday.
31. David has already read a lot of adventure stories.
32. Mike always listens to rock music