What is the sum of all even numbers within 100? As the title! Which is it! depressed

What is the sum of all even numbers within 100? As the title! Which is it! depressed

2+4+6+..+100=(2+100)*50/2=2550

What are even numbers within 100

2,4,6,8,10,12,14,16,18,20,22,24,26,28,30,32,34,36,38,40,42,44,46,48,50,52,54,56,58,60,62,64,66,68,70,72,74,76,78,80,82,84,86,88,90,92,94,96,98,100

What is the sum of even numbers within 100?
Such as the title

（2+100）*25=2550

How to do 1 * 3 / 1 3 * 5 / 1 5 * 7 / 1. (2n-1) * (2n 1) / 1 = 21 / 10

1,53'5688*563\1

Use VB to calculate s = 1 + 2 / 3 + 3 / 5 + 4 / 7 +. When the value of item I is less than 10 ^ - 5, it ends

Dim s as integerdim x as integerdim y as integers = 0x = 1y = 1while (x / Y > 10 ^ - 5) s = S + X / YX = x + 1y = y + 2wend

VB calculation 1-1 / 3! + 1 / 5! - 1 / 7! + +(- 1) ^ (n-1) / (2n-1)! Please fill in the blanks
Private Sub Command1_ Click()
Dim i As Integer,j As Integer
Dim n As Integer
Dim s As Double
j=1
s=1
n = Val(Text1.Text)
For i = 2 To n
j=__________ 'calculate 1 / (2 * i-1)!
s=_______________ 'l cumulative general term
Next i
text2.text=str(s)

j * (2 * i - 2) * (2 * i - 1)
s + (-1) ^ (n - 1) / j

Known arithmetic sequence {an}, 3,7,11,15, find
Is 4m + 19 (m ∈ n) a term in an?
Solution: since 4m + 19 = 4 (M + 5) - 1, why is 4 (M + 5) - 1

an = 4n-1
4m+19 = 4(m+5) -1
=>4m + 19 (m ∈ n) is a term in an

Known sequence 3, 7, 11 139 and 2, 9, 16 , 142, then the number of all their public items is ()
A. 4B. 5C. 6D. 7

The sequence 3, 7, 11 The general term formula of, 139 is an = 4n-1139, which is the 35th term of the sequence The general term formula of, 142 is BM = 7m-5142, which is the 21st term of the sequence The n-th term and the sequence 2, 9, 16 , 142, then 4N-1 = 7m-5, n = 7m − 44 = 7m4-1, M is a multiple of 4, M is less than 21, n is less than 35, so m can only be 4, 8, 12, 16, 20. At this time, the corresponding values of N are 6, 13, 20, 27, 34, so the number of public items is 5. So select B

Arithmetic sequence - 3, - 7, - 11, - 15 The general term formula of

An = (- 3) + (- 4) * (n-1) = 1-4n (n ≥ 1, n is a natural number)