Tính :A= [(2018/1)+(2017/2)+(2016/3)+(2015/4)+...+(4/2015)+(3/2016)+(2/2017)+(1/2018)]/[(2019/2)+(2019/3)+(2019/4)+(2019/5)+...+(2019/2015)+(2019/2016)+(2019/2017)+(2019/2018)+(2019/2019)]

Tính :A= [(2018/1)+(2017/2)+(2016/3)+(2015/4)+...+(4/2015)+(3/2016)+(2/2017)+(1/2018)]/[(2019/1)+(2019/2)+(2019/3)+(2019/4)+...+(2019/2015)+(2019/2016)+(2019/2017)+(2019/2018)+(2019/2019)]

chứng minh 2015/2016 + 2016/2017 + 2017/2018 + 2018/2019 + 2019/2020 + 2020/2015 > 6

Tính:

A=2019/2018 - 2018/2017 + 2017/2016 - 2016/2015

B=1/2019 - 1/2018 + 1/2017 - 1/2016

C=1/2017 - 1/2016 + 1/2015 - 1/2014

a)
Ta có: 2015/2016=1-1/2016
2016/2017=1--1/2020.So sánh 1/2016 và 1/2017 được 1/2016>1/2017
Suy ra 2015/2016<2016/2017
b) 2018/2018=1
   2019/2018>1

Vậy 2018/2018 <2019/2018
CHÚC BẠN HỌC TỐT NHÉ!!!

So sanh :\(\frac{2017}{2018}+\frac{2018}{2019}va\frac{2015}{2016}+\frac{2016}{2017}\)

So sánh \(\frac{2017}{2018}+\frac{2018}{2019}và\frac{2015}{2016}+\frac{2016}{2017}\)

Cho x,y>0 thỏa mãn

x^2015+y^2015=x^2016+y^2016=x^2017+y^2017

C/m: 1/x^2018+1/y^2018=1/x^2019+1/y^2019

\(2015^{2016}+2016^{2017}+2017^{2018}+2018^{2019}\) chứng tỏ rằng tổng không là số chính phương