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BÀI NÀY LỚP 5 CHỊU

BÀI NÀY CHO SANG LỚP 8

Hình như câu 2 là của lớp 10?

lớp 5 á

Ta có: \(\frac{2003.2004}{2003.2004}=1\)

1+1=2

Vậy \(\frac{2003.2004}{2003.2004}\)+1 > \(\frac{2004}{2005}\)

TL: dấu này >

Bài 1:

a. \(R=p\dfrac{l}{S}=1,10.10^{-6}\dfrac{30}{0,3\cdot10^{-6}}=110\Omega\)

b. \(I=U:R=220:110=2A\)

Bài 2:

a. \(R=R1+R2=30+50=80\Omega\)

b. \(I=I1=I2=0,25A\left(R1ntR2\right)\)

\(\left\{{}\begin{matrix}U1=I1\cdot R1=0,25\cdot30=7,5V\\U2=I2\cdot R2=0,25\cdot50=12,5V\\U=IR=0,25\cdot80=20V\end{matrix}\right.\)

Câu 1.

a)\(R=\rho\cdot\dfrac{l}{S}=1,1\cdot10^{-6}\cdot\dfrac{30}{0,3\cdot10^{-6}}=110\Omega\)

b)\(I=\dfrac{U}{R}=\dfrac{220}{110}=2A\)

Câu 2.

a)\(R_{AB}=R_1+R_2=30+50=80\Omega\)

b)\(I_1=I_2=I_A=0,25A\)

   \(U_1=R_1\cdot I_1=30\cdot0,25=7,5V\)

   \(U_2=R_2\cdot I_2=50\cdot0,25=12,5V\)

   \(U_{AB}=U_1+U_2=7,5+12,5=20V\)

Câu 3.

a)\(R_{AB}=\dfrac{R_1\cdot R_2}{R_1+R_2}=\dfrac{600\cdot900}{600+900}=360\Omega\)

b)\(U_1=U_2=U_m=220V\)

   \(I_1=\dfrac{U_1}{R_1}=\dfrac{220}{600}=\dfrac{11}{30}A\)

   \(I_2=\dfrac{U_2}{R_2}=\dfrac{220}{900}=\dfrac{11}{45}A\)

   \(I_m=I_1+I_2=\dfrac{11}{30}+\dfrac{11}{45}=\dfrac{11}{18}A\)

Bài 3:

a. \(R=\dfrac{R1\cdot R2}{R1+R2}=\dfrac{600\cdot900}{600+900}=360\Omega\)

b. \(U=U1=U2=220V\left(R1//R2\right)\)

\(\left\{{}\begin{matrix}I1=U1:R1=220:600=\dfrac{11}{30}A\\I2=U2:R2=220:900=\dfrac{11}{45}A\\I=U:R=220:360=\dfrac{11}{18}A\end{matrix}\right.\)

1. In spite of being a poor student, he studied very well

2. Despite the bad weather, she went to school on time

3. Despite having a physical handicap, she has become a successful woman

4. In spite of having not finished the paper, he went to sleep

5. Despite having a lot of noise in the city, I prefer living there

1. In spite of being a poor student, he studied very well

2. Despite the fact that the weather was bad, she went to school on time.

Đề bài đâu bạn?

+) Nếu a>0 khi đó VT>225 (với mọi b là số tự nhiên) => MT

=>a=0

=> (3b+1)(b+1)=225

=> tìm đc b

bạn cho mình hỏi b=bao nhieu

Đáp án là:

a = 0

b = 8