# Đã cho một số n in tổng của tất cả các số chẵn từ 1 đến n trong C++

`Sum of first 20 Even numbers is: 420`
9
`                 Sum of first n even numbers = n * (n + 1).`
5
`                 Sum of first n even numbers = n * (n + 1).`
6
`Sum of first 20 Even numbers is: 420`
4
`                 Sum of first n even numbers = n * (n + 1).`
8

`                 Sum of first n even numbers = n * (n + 1).`
9
```Sum of first n terms of an A.P.(Arithmetic Progression)
= (n/2) * [2*a + (n-1)*d].....(i)
where, a is the first term of the series and d is
the difference between the adjacent terms of the series.

Here, a = 2, d = 2, applying these values to eq.(i), we get
Sum = (n/2) * [2*2 + (n-1)*2]
= (n/2) * [4 + 2*n - 2]
= (n/2) * (2*n + 2)
= n * (n + 1)```
0

`                 Sum of first n even numbers = n * (n + 1).`
9
```Sum of first n terms of an A.P.(Arithmetic Progression)
= (n/2) * [2*a + (n-1)*d].....(i)
where, a is the first term of the series and d is
the difference between the adjacent terms of the series.

Here, a = 2, d = 2, applying these values to eq.(i), we get
Sum = (n/2) * [2*2 + (n-1)*2]
= (n/2) * [4 + 2*n - 2]
= (n/2) * (2*n + 2)
= n * (n + 1)```
2

`                 Sum of first n even numbers = n * (n + 1).`
9
```Sum of first n terms of an A.P.(Arithmetic Progression)
= (n/2) * [2*a + (n-1)*d].....(i)
where, a is the first term of the series and d is
the difference between the adjacent terms of the series.

Here, a = 2, d = 2, applying these values to eq.(i), we get
Sum = (n/2) * [2*2 + (n-1)*2]
= (n/2) * [4 + 2*n - 2]
= (n/2) * (2*n + 2)
= n * (n + 1)```
4

`Sum of first 20 Even numbers is: 420`
9
```Sum of first n terms of an A.P.(Arithmetic Progression)
= (n/2) * [2*a + (n-1)*d].....(i)
where, a is the first term of the series and d is
the difference between the adjacent terms of the series.

Here, a = 2, d = 2, applying these values to eq.(i), we get
Sum = (n/2) * [2*2 + (n-1)*2]
= (n/2) * [4 + 2*n - 2]
= (n/2) * (2*n + 2)
= n * (n + 1)```
6

`Sum of first 20 Even numbers is: 420`
9
```Sum of first n terms of an A.P.(Arithmetic Progression)
= (n/2) * [2*a + (n-1)*d].....(i)
where, a is the first term of the series and d is
the difference between the adjacent terms of the series.

Here, a = 2, d = 2, applying these values to eq.(i), we get
Sum = (n/2) * [2*2 + (n-1)*2]
= (n/2) * [4 + 2*n - 2]
= (n/2) * (2*n + 2)
= n * (n + 1)```
8

`Sum of first 20 Even numbers is: 420`
9
`Sum of first 20 Even numbers is: 420`
0
`Sum of first 20 Even numbers is: 420`
1

```Sum of first n terms of an A.P.(Arithmetic Progression)
= (n/2) * [2*a + (n-1)*d].....(i)
where, a is the first term of the series and d is
the difference between the adjacent terms of the series.

Here, a = 2, d = 2, applying these values to eq.(i), we get
Sum = (n/2) * [2*2 + (n-1)*2]
= (n/2) * [4 + 2*n - 2]
= (n/2) * (2*n + 2)
= n * (n + 1)```
6

`Sum of first 20 Even numbers is: 420`
3

`Sum of first 20 Even numbers is: 420`
4
`Sum of first 20 Even numbers is: 420`
5

`Sum of first 20 Even numbers is: 420`
8

`Sum of first 20 Even numbers is: 420`
9
`Sum of first 20 Even numbers is: 420`
4
`Sum of first 20 Even numbers is: 420`
9

`Sum of first 20 Even numbers is: 420`
9
`Sum of first 20 Even numbers is: 420`
1____02
`Sum of first 20 Even numbers is: 420`
3

`Sum of first 20 Even numbers is: 420`
4
`Sum of first 20 Even numbers is: 420`
5
`Sum of first 20 Even numbers is: 420`
6
`Sum of first 20 Even numbers is: 420`
7

`Sum of first 20 Even numbers is: 420`
9
`Sum of first 20 Even numbers is: 420`
0
`                 Sum of first n even numbers = n * (n + 1).`
610

```Sum of first n terms of an A.P.(Arithmetic Progression)
= (n/2) * [2*a + (n-1)*d].....(i)
where, a is the first term of the series and d is
the difference between the adjacent terms of the series.

Here, a = 2, d = 2, applying these values to eq.(i), we get
Sum = (n/2) * [2*2 + (n-1)*2]
= (n/2) * [4 + 2*n - 2]
= (n/2) * (2*n + 2)
= n * (n + 1)```
6

## Java

`                 Sum of first n even numbers = n * (n + 1).`
612

`                 Sum of first n even numbers = n * (n + 1).`
613

`                 Sum of first n even numbers = n * (n + 1).`
614
`                 Sum of first n even numbers = n * (n + 1).`
615

`                 Sum of first n even numbers = n * (n + 1).`
614
`                 Sum of first n even numbers = n * (n + 1).`
617

`                 Sum of first n even numbers = n * (n + 1).`
618
`                 Sum of first n even numbers = n * (n + 1).`
619
`                 Sum of first n even numbers = n * (n + 1).`
700

`Sum of first 20 Even numbers is: 420`
9

`Sum of first 20 Even numbers is: 420`
9
`Sum of first 20 Even numbers is: 420`
2

`Sum of first 20 Even numbers is: 420`
9
`                 Sum of first n even numbers = n * (n + 1).`
70

`Sum of first 20 Even numbers is: 420`
9
`                 Sum of first n even numbers = n * (n + 1).`
707
`Sum of first 20 Even numbers is: 420`
4
`Sum of first 20 Even numbers is: 420`
5
`Sum of first 20 Even numbers is: 420`
4
`Sum of first 20 Even numbers is: 420`
7

`Sum of first 20 Even numbers is: 420`
9
`Sum of first 20 Even numbers is: 420`
8

`                 Sum of first n even numbers = n * (n + 1).`
9
`Sum of first 20 Even numbers is: 420`
4
`                 Sum of first n even numbers = n * (n + 1).`
736
`                 Sum of first n even numbers = n * (n + 1).`
737
`                 Sum of first n even numbers = n * (n + 1).`
738
`                 Sum of first n even numbers = n * (n + 1).`
739
`                 Sum of first n even numbers = n * (n + 1).`
770

`                 Sum of first n even numbers = n * (n + 1).`
9
`                 Sum of first n even numbers = n * (n + 1).`
3

`                 Sum of first n even numbers = n * (n + 1).`
9
`                 Sum of first n even numbers = n * (n + 1).`
5
`                 Sum of first n even numbers = n * (n + 1).`
6
`Sum of first 20 Even numbers is: 420`
4
`                 Sum of first n even numbers = n * (n + 1).`
777
`                 Sum of first n even numbers = n * (n + 1).`
778
`                 Sum of first n even numbers = n * (n + 1).`
779

`Sum of first 20 Even numbers is: 420`
00
```Sum of first n terms of an A.P.(Arithmetic Progression)
= (n/2) * [2*a + (n-1)*d].....(i)
where, a is the first term of the series and d is
the difference between the adjacent terms of the series.

Here, a = 2, d = 2, applying these values to eq.(i), we get
Sum = (n/2) * [2*2 + (n-1)*2]
= (n/2) * [4 + 2*n - 2]
= (n/2) * (2*n + 2)
= n * (n + 1)```
0

`Sum of first 20 Even numbers is: 420`
00
```Sum of first n terms of an A.P.(Arithmetic Progression)
= (n/2) * [2*a + (n-1)*d].....(i)
where, a is the first term of the series and d is
the difference between the adjacent terms of the series.

Here, a = 2, d = 2, applying these values to eq.(i), we get
Sum = (n/2) * [2*2 + (n-1)*2]
= (n/2) * [4 + 2*n - 2]
= (n/2) * (2*n + 2)
= n * (n + 1)```
2

`Sum of first 20 Even numbers is: 420`
00
`Sum of first 20 Even numbers is: 420`
05
`                 Sum of first n even numbers = n * (n + 1).`
737
`                 Sum of first n even numbers = n * (n + 1).`
770

`                 Sum of first n even numbers = n * (n + 1).`
9
```Sum of first n terms of an A.P.(Arithmetic Progression)
= (n/2) * [2*a + (n-1)*d].....(i)
where, a is the first term of the series and d is
the difference between the adjacent terms of the series.

Here, a = 2, d = 2, applying these values to eq.(i), we get
Sum = (n/2) * [2*2 + (n-1)*2]
= (n/2) * [4 + 2*n - 2]
= (n/2) * (2*n + 2)
= n * (n + 1)```
6

`                 Sum of first n even numbers = n * (n + 1).`
9
```Sum of first n terms of an A.P.(Arithmetic Progression)
= (n/2) * [2*a + (n-1)*d].....(i)
where, a is the first term of the series and d is
the difference between the adjacent terms of the series.

Here, a = 2, d = 2, applying these values to eq.(i), we get
Sum = (n/2) * [2*2 + (n-1)*2]
= (n/2) * [4 + 2*n - 2]
= (n/2) * (2*n + 2)
= n * (n + 1)```
8

`                 Sum of first n even numbers = n * (n + 1).`
9
`Sum of first 20 Even numbers is: 420`
0
`Sum of first 20 Even numbers is: 420`
14

`Sum of first 20 Even numbers is: 420`
9
```Sum of first n terms of an A.P.(Arithmetic Progression)
= (n/2) * [2*a + (n-1)*d].....(i)
where, a is the first term of the series and d is
the difference between the adjacent terms of the series.

Here, a = 2, d = 2, applying these values to eq.(i), we get
Sum = (n/2) * [2*2 + (n-1)*2]
= (n/2) * [4 + 2*n - 2]
= (n/2) * (2*n + 2)
= n * (n + 1)```
6

`Sum of first 20 Even numbers is: 420`
9

`Sum of first 20 Even numbers is: 420`
9
`Sum of first 20 Even numbers is: 420`
19

`Sum of first 20 Even numbers is: 420`
9
`                 Sum of first n even numbers = n * (n + 1).`
618
`                 Sum of first n even numbers = n * (n + 1).`
707
`Sum of first 20 Even numbers is: 420`
23
`Sum of first 20 Even numbers is: 420`
24

`Sum of first 20 Even numbers is: 420`
9
`Sum of first 20 Even numbers is: 420`
8

`                 Sum of first n even numbers = n * (n + 1).`
9
`Sum of first 20 Even numbers is: 420`
4
`Sum of first 20 Even numbers is: 420`
29
`Sum of first 20 Even numbers is: 420`
30
`                 Sum of first n even numbers = n * (n + 1).`
770

`                 Sum of first n even numbers = n * (n + 1).`
9
`Sum of first 20 Even numbers is: 420`
33____02
`Sum of first 20 Even numbers is: 420`
35

________ 036 ________ 06 ________ 038

`Sum of first 20 Even numbers is: 420`
36
`Sum of first 20 Even numbers is: 420`
40

`Sum of first 20 Even numbers is: 420`
9
```Sum of first n terms of an A.P.(Arithmetic Progression)
= (n/2) * [2*a + (n-1)*d].....(i)
where, a is the first term of the series and d is
the difference between the adjacent terms of the series.

Here, a = 2, d = 2, applying these values to eq.(i), we get
Sum = (n/2) * [2*2 + (n-1)*2]
= (n/2) * [4 + 2*n - 2]
= (n/2) * (2*n + 2)
= n * (n + 1)```
6

```Sum of first n terms of an A.P.(Arithmetic Progression)
= (n/2) * [2*a + (n-1)*d].....(i)
where, a is the first term of the series and d is
the difference between the adjacent terms of the series.

Here, a = 2, d = 2, applying these values to eq.(i), we get
Sum = (n/2) * [2*2 + (n-1)*2]
= (n/2) * [4 + 2*n - 2]
= (n/2) * (2*n + 2)
= n * (n + 1)```
6

`Sum of first 20 Even numbers is: 420`
44

## Python3

`Sum of first 20 Even numbers is: 420`
45

`Sum of first 20 Even numbers is: 420`
46

`Sum of first 20 Even numbers is: 420`
9

`Sum of first 20 Even numbers is: 420`
48

`Sum of first 20 Even numbers is: 420`
46

`Sum of first 20 Even numbers is: 420`
50
`Sum of first 20 Even numbers is: 420`
51

`Sum of first 20 Even numbers is: 420`
9
`Sum of first 20 Even numbers is: 420`
53
`Sum of first 20 Even numbers is: 420`
54
`                 Sum of first n even numbers = n * (n + 1).`
737

`Sum of first 20 Even numbers is: 420`
9
`Sum of first 20 Even numbers is: 420`
57
`Sum of first 20 Even numbers is: 420`
54
`                 Sum of first n even numbers = n * (n + 1).`
739

`Sum of first 20 Even numbers is: 420`
9
`Sum of first 20 Even numbers is: 420`
61
`Sum of first 20 Even numbers is: 420`
54
`                 Sum of first n even numbers = n * (n + 1).`
778

`Sum of first 20 Even numbers is: 420`
9

`Sum of first 20 Even numbers is: 420`
9
`Sum of first 20 Even numbers is: 420`
66

`Sum of first 20 Even numbers is: 420`
9
`Sum of first 20 Even numbers is: 420`
68
`Sum of first 20 Even numbers is: 420`
69______054
`Sum of first 20 Even numbers is: 420`
71

`                 Sum of first n even numbers = n * (n + 1).`
9
`Sum of first 20 Even numbers is: 420`
57
`Sum of first 20 Even numbers is: 420`
38
`Sum of first 20 Even numbers is: 420`
54
`Sum of first 20 Even numbers is: 420`
53

`                 Sum of first n even numbers = n * (n + 1).`
9

`                 Sum of first n even numbers = n * (n + 1).`
9
`Sum of first 20 Even numbers is: 420`
79

`                 Sum of first n even numbers = n * (n + 1).`
9
`Sum of first 20 Even numbers is: 420`
53____038
`Sum of first 20 Even numbers is: 420`
54
`                 Sum of first n even numbers = n * (n + 1).`
737

`                 Sum of first n even numbers = n * (n + 1).`
9
`Sum of first 20 Even numbers is: 420`
61
`Sum of first 20 Even numbers is: 420`
54
`Sum of first 20 Even numbers is: 420`
61
`Sum of first 20 Even numbers is: 420`
38
`                 Sum of first n even numbers = n * (n + 1).`
778

`Sum of first 20 Even numbers is: 420`
9
`Sum of first 20 Even numbers is: 420`
0
`Sum of first 20 Even numbers is: 420`
57

`Sum of first 20 Even numbers is: 420`
94

`Sum of first 20 Even numbers is: 420`
95
`Sum of first 20 Even numbers is: 420`
54
`Sum of first 20 Even numbers is: 420`
30

`Sum of first 20 Even numbers is: 420`
98
`                 Sum of first n even numbers = n * (n + 1).`
6
`                 Sum of first n even numbers = n * (n + 1).`
00
`                 Sum of first n even numbers = n * (n + 1).`
01
`                 Sum of first n even numbers = n * (n + 1).`
02
`                 Sum of first n even numbers = n * (n + 1).`
03

`                 Sum of first n even numbers = n * (n + 1).`
04
`                 Sum of first n even numbers = n * (n + 1).`
05

`                 Sum of first n even numbers = n * (n + 1).`
06

## C#

`                 Sum of first n even numbers = n * (n + 1).`
07

`                 Sum of first n even numbers = n * (n + 1).`
613

`                 Sum of first n even numbers = n * (n + 1).`
77
`                 Sum of first n even numbers = n * (n + 1).`
10

`                 Sum of first n even numbers = n * (n + 1).`
618
`                 Sum of first n even numbers = n * (n + 1).`
619
`                 Sum of first n even numbers = n * (n + 1).`
13

`Sum of first 20 Even numbers is: 420`
9
`Sum of first 20 Even numbers is: 420`
2

`Sum of first 20 Even numbers is: 420`
9
`                 Sum of first n even numbers = n * (n + 1).`
70

`Sum of first 20 Even numbers is: 420`
9
`                 Sum of first n even numbers = n * (n + 1).`
707
`Sum of first 20 Even numbers is: 420`
4
`Sum of first 20 Even numbers is: 420`
5
`Sum of first 20 Even numbers is: 420`
4
`Sum of first 20 Even numbers is: 420`
7

`Sum of first 20 Even numbers is: 420`
9
`Sum of first 20 Even numbers is: 420`
8

`                 Sum of first n even numbers = n * (n + 1).`
9
`Sum of first 20 Even numbers is: 420`
4
`                 Sum of first n even numbers = n * (n + 1).`
1

`                 Sum of first n even numbers = n * (n + 1).`
9
`                 Sum of first n even numbers = n * (n + 1).`
3

`                 Sum of first n even numbers = n * (n + 1).`
9
`                 Sum of first n even numbers = n * (n + 1).`
5
`                 Sum of first n even numbers = n * (n + 1).`
6
`Sum of first 20 Even numbers is: 420`
4
`                 Sum of first n even numbers = n * (n + 1).`
8

`Sum of first 20 Even numbers is: 420`
00
```Sum of first n terms of an A.P.(Arithmetic Progression)
= (n/2) * [2*a + (n-1)*d].....(i)
where, a is the first term of the series and d is
the difference between the adjacent terms of the series.

Here, a = 2, d = 2, applying these values to eq.(i), we get
Sum = (n/2) * [2*2 + (n-1)*2]
= (n/2) * [4 + 2*n - 2]
= (n/2) * (2*n + 2)
= n * (n + 1)```
0

`Sum of first 20 Even numbers is: 420`
00
```Sum of first n terms of an A.P.(Arithmetic Progression)
= (n/2) * [2*a + (n-1)*d].....(i)
where, a is the first term of the series and d is
the difference between the adjacent terms of the series.

Here, a = 2, d = 2, applying these values to eq.(i), we get
Sum = (n/2) * [2*2 + (n-1)*2]
= (n/2) * [4 + 2*n - 2]
= (n/2) * (2*n + 2)
= n * (n + 1)```
2

`Sum of first 20 Even numbers is: 420`
00
```Sum of first n terms of an A.P.(Arithmetic Progression)
= (n/2) * [2*a + (n-1)*d].....(i)
where, a is the first term of the series and d is
the difference between the adjacent terms of the series.

Here, a = 2, d = 2, applying these values to eq.(i), we get
Sum = (n/2) * [2*2 + (n-1)*2]
= (n/2) * [4 + 2*n - 2]
= (n/2) * (2*n + 2)
= n * (n + 1)```
4

`                 Sum of first n even numbers = n * (n + 1).`
9
```Sum of first n terms of an A.P.(Arithmetic Progression)
= (n/2) * [2*a + (n-1)*d].....(i)
where, a is the first term of the series and d is
the difference between the adjacent terms of the series.

Here, a = 2, d = 2, applying these values to eq.(i), we get
Sum = (n/2) * [2*2 + (n-1)*2]
= (n/2) * [4 + 2*n - 2]
= (n/2) * (2*n + 2)
= n * (n + 1)```
6

`                 Sum of first n even numbers = n * (n + 1).`
9
```Sum of first n terms of an A.P.(Arithmetic Progression)
= (n/2) * [2*a + (n-1)*d].....(i)
where, a is the first term of the series and d is
the difference between the adjacent terms of the series.

Here, a = 2, d = 2, applying these values to eq.(i), we get
Sum = (n/2) * [2*2 + (n-1)*2]
= (n/2) * [4 + 2*n - 2]
= (n/2) * (2*n + 2)
= n * (n + 1)```
8

`                 Sum of first n even numbers = n * (n + 1).`
9
`Sum of first 20 Even numbers is: 420`
0
`Sum of first 20 Even numbers is: 420`
1

`Sum of first 20 Even numbers is: 420`
9
```Sum of first n terms of an A.P.(Arithmetic Progression)
= (n/2) * [2*a + (n-1)*d].....(i)
where, a is the first term of the series and d is
the difference between the adjacent terms of the series.

Here, a = 2, d = 2, applying these values to eq.(i), we get
Sum = (n/2) * [2*2 + (n-1)*2]
= (n/2) * [4 + 2*n - 2]
= (n/2) * (2*n + 2)
= n * (n + 1)```
6

`Sum of first 20 Even numbers is: 420`
9
`Sum of first 20 Even numbers is: 420`
19

`Sum of first 20 Even numbers is: 420`
9
`                 Sum of first n even numbers = n * (n + 1).`
618
`                 Sum of first n even numbers = n * (n + 1).`
707
`Sum of first 20 Even numbers is: 420`
23
`                 Sum of first n even numbers = n * (n + 1).`
57

`Sum of first 20 Even numbers is: 420`
9
`Sum of first 20 Even numbers is: 420`
8

`                 Sum of first n even numbers = n * (n + 1).`
9
`Sum of first 20 Even numbers is: 420`
4
`Sum of first 20 Even numbers is: 420`
9

`                 Sum of first n even numbers = n * (n + 1).`
9

`                 Sum of first n even numbers = n * (n + 1).`
9
`                 Sum of first n even numbers = n * (n + 1).`
65
`Sum of first 20 Even numbers is: 420`
2
`                 Sum of first n even numbers = n * (n + 1).`
67

`Sum of first 20 Even numbers is: 420`
4
`Sum of first 20 Even numbers is: 420`
38
`Sum of first 20 Even numbers is: 420`
6
`                 Sum of first n even numbers = n * (n + 1).`
71

`Sum of first 20 Even numbers is: 420`
9
```Sum of first n terms of an A.P.(Arithmetic Progression)
= (n/2) * [2*a + (n-1)*d].....(i)
where, a is the first term of the series and d is
the difference between the adjacent terms of the series.

Here, a = 2, d = 2, applying these values to eq.(i), we get
Sum = (n/2) * [2*2 + (n-1)*2]
= (n/2) * [4 + 2*n - 2]
= (n/2) * (2*n + 2)
= n * (n + 1)```
6

```Sum of first n terms of an A.P.(Arithmetic Progression)
= (n/2) * [2*a + (n-1)*d].....(i)
where, a is the first term of the series and d is
the difference between the adjacent terms of the series.

Here, a = 2, d = 2, applying these values to eq.(i), we get
Sum = (n/2) * [2*2 + (n-1)*2]
= (n/2) * [4 + 2*n - 2]
= (n/2) * (2*n + 2)
= n * (n + 1)```
6

`                 Sum of first n even numbers = n * (n + 1).`
75

## PHP

`                 Sum of first n even numbers = n * (n + 1).`
76

`                 Sum of first n even numbers = n * (n + 1).`
77

`                 Sum of first n even numbers = n * (n + 1).`
70

`Sum of first 20 Even numbers is: 420`
2

`                 Sum of first n even numbers = n * (n + 1).`
70

`                 Sum of first n even numbers = n * (n + 1).`
81
`Sum of first 20 Even numbers is: 420`
5____183
`                 Sum of first n even numbers = n * (n + 1).`
84

`Sum of first 20 Even numbers is: 420`
8

`Sum of first 20 Even numbers is: 420`
9
`                 Sum of first n even numbers = n * (n + 1).`
87
`                 Sum of first n even numbers = n * (n + 1).`
88

`Sum of first 20 Even numbers is: 420`
9
`                 Sum of first n even numbers = n * (n + 1).`
90
`                 Sum of first n even numbers = n * (n + 1).`
91

`Sum of first 20 Even numbers is: 420`
9
`                 Sum of first n even numbers = n * (n + 1).`
3

`Sum of first 20 Even numbers is: 420`
9
`                 Sum of first n even numbers = n * (n + 1).`
5
`                 Sum of first n even numbers = n * (n + 1).`
6
`                 Sum of first n even numbers = n * (n + 1).`
97
`                 Sum of first n even numbers = n * (n + 1).`
98
`                 Sum of first n even numbers = n * (n + 1).`
97
```Sum of first n terms of an A.P.(Arithmetic Progression)
= (n/2) * [2*a + (n-1)*d].....(i)
where, a is the first term of the series and d is
the difference between the adjacent terms of the series.

Here, a = 2, d = 2, applying these values to eq.(i), we get
Sum = (n/2) * [2*2 + (n-1)*2]
= (n/2) * [4 + 2*n - 2]
= (n/2) * (2*n + 2)
= n * (n + 1)```
00
`                 Sum of first n even numbers = n * (n + 1).`
83
`                 Sum of first n even numbers = n * (n + 1).`
770
`                 Sum of first n even numbers = n * (n + 1).`
97
```Sum of first n terms of an A.P.(Arithmetic Progression)
= (n/2) * [2*a + (n-1)*d].....(i)
where, a is the first term of the series and d is
the difference between the adjacent terms of the series.

Here, a = 2, d = 2, applying these values to eq.(i), we get
Sum = (n/2) * [2*2 + (n-1)*2]
= (n/2) * [4 + 2*n - 2]
= (n/2) * (2*n + 2)
= n * (n + 1)```
04

`                 Sum of first n even numbers = n * (n + 1).`
9
`                 Sum of first n even numbers = n * (n + 1).`
90
```Sum of first n terms of an A.P.(Arithmetic Progression)
= (n/2) * [2*a + (n-1)*d].....(i)
where, a is the first term of the series and d is
the difference between the adjacent terms of the series.

Here, a = 2, d = 2, applying these values to eq.(i), we get
Sum = (n/2) * [2*2 + (n-1)*2]
= (n/2) * [4 + 2*n - 2]
= (n/2) * (2*n + 2)
= n * (n + 1)```
07
`                 Sum of first n even numbers = n * (n + 1).`
87
`                 Sum of first n even numbers = n * (n + 1).`
770

`                 Sum of first n even numbers = n * (n + 1).`
9
```Sum of first n terms of an A.P.(Arithmetic Progression)
= (n/2) * [2*a + (n-1)*d].....(i)
where, a is the first term of the series and d is
the difference between the adjacent terms of the series.

Here, a = 2, d = 2, applying these values to eq.(i), we get
Sum = (n/2) * [2*2 + (n-1)*2]
= (n/2) * [4 + 2*n - 2]
= (n/2) * (2*n + 2)
= n * (n + 1)```
2

`                 Sum of first n even numbers = n * (n + 1).`
9
`                 Sum of first n even numbers = n * (n + 1).`
87
```Sum of first n terms of an A.P.(Arithmetic Progression)
= (n/2) * [2*a + (n-1)*d].....(i)
where, a is the first term of the series and d is
the difference between the adjacent terms of the series.

Here, a = 2, d = 2, applying these values to eq.(i), we get
Sum = (n/2) * [2*2 + (n-1)*2]
= (n/2) * [4 + 2*n - 2]
= (n/2) * (2*n + 2)
= n * (n + 1)```
14

`Sum of first 20 Even numbers is: 420`
9
```Sum of first n terms of an A.P.(Arithmetic Progression)
= (n/2) * [2*a + (n-1)*d].....(i)
where, a is the first term of the series and d is
the difference between the adjacent terms of the series.

Here, a = 2, d = 2, applying these values to eq.(i), we get
Sum = (n/2) * [2*2 + (n-1)*2]
= (n/2) * [4 + 2*n - 2]
= (n/2) * (2*n + 2)
= n * (n + 1)```
6

`Sum of first 20 Even numbers is: 420`
9
```Sum of first n terms of an A.P.(Arithmetic Progression)
= (n/2) * [2*a + (n-1)*d].....(i)
where, a is the first term of the series and d is
the difference between the adjacent terms of the series.

Here, a = 2, d = 2, applying these values to eq.(i), we get
Sum = (n/2) * [2*2 + (n-1)*2]
= (n/2) * [4 + 2*n - 2]
= (n/2) * (2*n + 2)
= n * (n + 1)```
8

`Sum of first 20 Even numbers is: 420`
9
`Sum of first 20 Even numbers is: 420`
0
`                 Sum of first n even numbers = n * (n + 1).`
6
`Sum of first 20 Even numbers is: 420`
4
`                 Sum of first n even numbers = n * (n + 1).`
7311
`                 Sum of first n even numbers = n * (n + 1).`
7312______2737
`                 Sum of first n even numbers = n * (n + 1).`
84
`Sum of first 20 Even numbers is: 420`
01
`                 Sum of first n even numbers = n * (n + 1).`
6
`                 Sum of first n even numbers = n * (n + 1).`
737
`Sum of first 20 Even numbers is: 420`
38
`                 Sum of first n even numbers = n * (n + 1).`
7319

### Làm cách nào để in tổng các số chẵn trong C?

Chương trình. Viết chương trình tìm tổng các số chẵn bằng ngôn ngữ C. .
#include .
int chính ()
int i, n, tổng=0;
printf("Nhập số bất kỳ. ");
scanf("%d", &n);
for(i=2; i<=n; i+=2)

### Làm thế nào để tìm tổng của n số chẵn đầu tiên trong C?

Để tìm tổng của các số chẵn, chúng ta cần lặp qua các số chẵn từ 1 đến n. Khởi tạo một vòng lặp từ 2 đến N và tăng 2 trên mỗi lần lặp. Cấu trúc vòng lặp sẽ giống như for(i=2; i<=N; i+=2). Bên trong thân vòng lặp thêm giá trị trước đó của tổng với i i. e. tổng = tổng + tôi

### Từ 1 đến n có bao nhiêu số chẵn?

10 là số chẵn nhỏ nhất có hai chữ số. Có tổng 50 các số chẵn từ 1 đến 100. 2 là số nguyên tố chẵn duy nhất. Các số chia hết cho 2 là số chẵn.

### Làm cách nào để in các số chẵn từ 1 đến 100 trong C?

Viết chương trình C in tất cả các số chẵn từ 1 đến 100. .
int main(){
int tôi;
cho (i=1;i<=100;i++){
nếu(i%2==0){
printf("%d\n",i);