so sánh a= 2020^15+1/2020^16+1 và b=2020^12+1/2020^13+1 18/11/2021 Bởi Sadie so sánh a= 2020^15+1/2020^16+1 và b=2020^12+1/2020^13+1
Ta có : A = 2020^15+1/2020^16+1 => 2020A = 2020^16+2020/2020^16+1 = 2020^16+1+2019/2020^16+1 = 1 + 2019/2020^16+1 Ta lại có : B = 2020^12+1//2020^13+1 => 2020B = 2020^13+2020/2020^13+1 = 2020^13+1+2019/2020^13+1 = 1 + 2019/2020^13+1 Vì 2019/2020^16+1 < 2019/2020^13+1 nên 1 + 2019/2020^16+1 < 1 + 2019/2020^13+1 => 2020A < 2020B => A < B Vậy A < B. Bình luận
Ta có : A = 2020^15+1/2020^16+1
=> 2020A = 2020^16+2020/2020^16+1 = 2020^16+1+2019/2020^16+1 = 1 + 2019/2020^16+1
Ta lại có : B = 2020^12+1//2020^13+1
=> 2020B = 2020^13+2020/2020^13+1 = 2020^13+1+2019/2020^13+1 = 1 + 2019/2020^13+1
Vì 2019/2020^16+1 < 2019/2020^13+1 nên 1 + 2019/2020^16+1 < 1 + 2019/2020^13+1
=> 2020A < 2020B
=> A < B
Vậy A < B.