\(1.\Rightarrow\left\{{}\begin{matrix}a,L=\dfrac{RS}{p}=\dfrac{10.0,1.10^{-6}}{0,4.10^{-5}}=0,25m\\b,\Rightarrow L=\dfrac{RS}{p}=\dfrac{30.0,5.10^{-6}}{1,7.10^{-8}}=882m\\c,\Rightarrow S=\dfrac{pL}{R}=\dfrac{0,5.10^{-6}.100}{50}=10^{-6}m^2\\\end{matrix}\right.\)

\(2.\Rightarrow Vàng,Nhôm,ĐỒng,Sắt\)

thông thường Đồng được sử dụng nhiều nhất do vật liệu không quá đắt 

so với Vàng,Nhôm

=2001

1 He is told to take a long rest

2 This plant isn't watered everyday

3 Beer is drunk all over the world

4 Uniform is worn to school by students

5 Reports are sent to the manager by the secretary in the afternoon

6 How many languages are spoken in Canada?

Bài 2

1 I was brought this dish by the waiter

2 I wasn't showed the special cameras 

3 Her ticket was showed to her friends

4 The broken cup was hidden in the drawer by Tom

5 The fridge wasmoved into the living room by his uncle

S = 1 + 4 + 7 + .....+ 82

dãy số trên là dãy số cách đều với khoảng cách là: 4 - 1 = 3

Số số hạng của dãy số trên là : ( 82 - 1) : 3 + 1  = 28 

Tổng S = ( 82+1).28 : 2 = 1162

1:

#include <bits/stdc++.h>

using namespace std;

long long t,i,n;

int main()

{

cin>>n;

t=0;

for (i=1; i<=n; i++) t+=i;

cout<<t;

return 0;

}

Bài 2: 

#include <bits/stdc++.h>

using namespace std;

long long n,i,t;

int main()

{

cin>>n;

t=0;

for (i=1; i<=n; i++)

if (i%2==0) t+=i;

cout<<t;

return 0;

}

Bài 3: 

#include <bits/stdc++.h>

using namespace std;

long long n,i,t;

int main()

{

cin>>n;

t=0;

for (i=1; i<=n; i++)

if (i%2!=0) t+=i;

cout<<t;

return 0;

}

Bài 4: 

#include <bits/stdc++.h>

using namespace std;

long long n,i,t;

int main()

{

cin>>n;

t=0;

for (i=1; i<=n; i++)

if (i%3==0) t+=i;

cout<<t;

return 0;

}

Bài 5: 

#include <bits/stdc++.h>

using namespace std;

long long n,i,t;

int main()

{

cin>>n;

t=1;

for (i=1; i<=n; i++)

t*=i;

cout<<t;

return 0;

}

Bài 3: 

a, PTHH: Mg + 2HCl \(\rightarrow\) MgCl₂ + H₂

b, \(n_{Mg}=\dfrac{7,2}{24}=0,3mol\)

\(n_{MgCl_2}=0,3.1=0,3mol\\ \Rightarrow m_{MgCl_2}=0,3.95=28,5g\)

c, \(n_{H_2}=0,3.1=0,3mol\\ \Rightarrow V_{H_2}=0,3.22,4=6,72l\)

Bài 4: 

a, PTHH: Zn + 2HCl \(\rightarrow\) ZnCl₂ + H₂

b,

 \(n_{Zn}=\dfrac{13}{65}=0,2mol\\ \Rightarrow n_{ZnCl_2}=0,2.1=0,2mol\\ m_{ZnCl_2}=0,2.136=27,2g\)

c, \(n_{H_2}=0,2.1=0,2mol\\ \Rightarrow V_{H_2}=0,2.22,4=4,48l\)

One of the biggest environmental impacts of human activities is air pollution