Ta có:
A=1/2+ 1/22+ ....+ 1/22019
2A= 2(1/2+ 1/22+...+1/22019 )
2A= 1+1/2+1/22+....+1/22018
2A-A= ( 1+1/2+1/22+....+1/22018) - (1/2+1/22+...+1/22019)
= 1- 1/22019
A= 1-1/22019= 22020/22019 - 1/22019= 22019+ 1/22019
Vậy 1/2+ 1/22+...+ 1/22019 = 22019+1/ 22019
tính A=(1/2+1/2^2+1/2^3 +.....+1/2^2019):(1-1/2^2019)
A=2020/20192+1 + 2020/20192+2 + 2020/20192+3 + ... + 2020/20192+2019. CMR 1<A<2.
A = 1 + 1/2(1+2) + 1/3(1 + 2 + 3) + 1/4(1 + 2 + 3 + 4) + ..........+ 1/2019(1 + 2 + 3 + 4 + .... + 2019)
1/2 = 1 phần hai
\(A=\left(\frac{1}{2}+\frac{1}{2^2}+\frac{1}{2^3}+...+\frac{1}{2^{2019}}\right):\left(1-\frac{1}{2^{2019}}\right)\)
Cho A=2020/20192+1 + 2020/20192+2 + 2020/20192+3 + ... + 2020/20192+2019. CMR 1<S<2.
Giúp tôi với! Tôi sẽ tick cho
[(1+2019/1)+(1+2019/2)+...+(1+2019/1020)]:[(1+1020/1)(1+1020/2)+....+(1+1020/2019)]
Mik sắp nộp r ai nhanh mik tick liền lun miễn là bài làm tốt 👍
Cho A = 2^2018 / 2^2018 + 3^2019 +3^2019/ 3^2019 + 5 ^ 2020 +5^2020 / 5^2020 + 2^2018
B=1/1*2+1/3*4+1/5*6+. . . +1/2019*2020
So sánh A và B
Giúp mk, mk kick cho
Cho P =1/2×1/3+...+1/2018+1/2019 và Q = 1/2018+2/2017 +...+ 2017/2+2018/1
Tính (Q - P .2019)^2019
Các bạn giúp mình với nha. Cảm ơn rất nhiều !
cho A = [ 1/1 + 1/2 + ....+ 1/2019 ] * [ 1*2*3*****2019]
CM A chia hết cho 2020
so sánh A và B biết:
A=\(\dfrac{2^{2018}}{2^{2018}+3^{2019}}\)+\(\dfrac{3^{2019}}{3^{2019}+5^{2020}}\)+\(\dfrac{5^{2020}}{5^{2020}+2^{2018}}\)
B=\(\dfrac{1}{1.2}\)+\(\dfrac{1}{3.4}\)+\(\dfrac{1}{5.6}\)+...+\(\dfrac{1}{2019.2020}\).