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4 tháng 5 2019

số số hạng là:

(100-2):2+1=98:2+1=50

vậy số số hạng là 50

Số số hạng là

(100 - 2) : 2 + 1 = 50 ( SSH )

Kick mk nha 

# USAS - 12 # 

15 tháng 1 2019

=(1+98-99-100)+(2-3-4+5)+(6-7-8+9)+...+(95-96-97+98)

=-100+0+0+0+0+0.........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................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A) SỐ 2020 CÓ THUỘC DÃY SỐ TRÊN

Số hạng thứ 100 của dãy số đó là :

2 + (100 - 1) x 4 = 398

Tổng 100 số hạng đầu tiên của dãy số đó là :

(2 + 398) x 100 : 2 = 20000

>>>>>> Lưu ý : Ta áp dụng các công thức với dãy số cách đều :

+) Tổng = (số đầu + số cuối) x số số hạng : 2.

+) Số hạng thứ n = số hạng thứ nhất + (n - 1) x khoảng cách giữa hai số liền nhau.

a) 1+(-2)+3+(-4)+..+19+(-20)                            {có 20-1+1=20(số hạng)}

 [1+(-2)]+[3+(-4)]+..+[19+(-20)]                       {có 20:2 = 10(tổng)}

=(-1)+(-1)+...+(-1)                                               {có 10 số hạng}

=(-1).10

= -10 

30 tháng 7 2015

a. st1: 2=1.2

st2: 4=2.2

st3: 6=3.2

...

st1005: 2010=1005.2

vậy số thứ 1005 là 2010

b. số số hạng:

(2010-2):2+1=1005(số)

tổng:

(2010+2).1005:2=1011030

1 tháng 10 2017

22 + 2+ 2+ 28

Vì 2 : 1 = 2; 4 : 2 = 2; 6 : 3 = 2; 8 : 4 = 2

Vậy số mũ của số hạng 100 là: 50

1 tháng 10 2017

2^2 + 2^4 + 2^6 + 2^8 + ...

Số mũ của số hạng 100 :

  100 . ( 4 - 2 ) . 2 = 202 

Bạn có thể thay 4 - 2 bằng 6 - 4 hoặc 8 - 6 ....

24 tháng 9 2015

xin lỗi ấn nhầm % đổi thành 5

& doi thanh 7