Toán So sanh A va B biet A=1/2+1/6+1/12+……+1/2009.2010 B=2010/2009 07/09/2021 By Rylee So sanh A va B biet A=1/2+1/6+1/12+……+1/2009.2010 B=2010/2009
Ta có: A= 1/2+ 1/6+ 1/12+..+ 1/2009.2020 = 1/1.2+ 1/2.3+..+ 1/2009.2020 = 1- 1/2+ 1/2- 1/3+..+ 1/2019- 1/2020 = 1- 1/2020 < 1( vì 1/2020> 0) Mà B= 2010/2009 > 1 ⇒ A< 1< B Vậy A< B Chúc bạn học tốt! Trả lời
A = 1/2 + 1/6 + 1/12 +……+ 1/2009.2010 = 1/1 x 2 + 1/2 x 3 + 1/3 x 4 +…..+ 1/2009 x 2010 = 1 – 1/2 + 1/2 – 1/3 +…..+ 1/2009 – 1/2010 = 1 – 1/2010 = 2009/2010 Ta thấy : 2009/2010 < 1 < 2010/2009 Vậy A < B Trả lời
Ta có:
A= 1/2+ 1/6+ 1/12+..+ 1/2009.2020
= 1/1.2+ 1/2.3+..+ 1/2009.2020
= 1- 1/2+ 1/2- 1/3+..+ 1/2019- 1/2020
= 1- 1/2020 < 1( vì 1/2020> 0)
Mà B= 2010/2009 > 1
⇒ A< 1< B
Vậy A< B
Chúc bạn học tốt!
A = 1/2 + 1/6 + 1/12 +……+ 1/2009.2010
= 1/1 x 2 + 1/2 x 3 + 1/3 x 4 +…..+ 1/2009 x 2010
= 1 – 1/2 + 1/2 – 1/3 +…..+ 1/2009 – 1/2010
= 1 – 1/2010
= 2009/2010
Ta thấy : 2009/2010 < 1 < 2010/2009
Vậy A < B