Question

So sánh A = \(\frac{2000^{2014}}{2000^{2015}-1}\) và B=\(\frac{2000^{2015}}{2000^{2016}-1}\)

Answer 1

 Ta có:

\(A=\frac{2000^{2014}}{2000^{2015}-1}=\frac{2000^{2014}\cdot2000}{\left(2000^{2015}-1\right)\cdot2000}=\frac{2000^{2015}}{2000^{2016}-2000}\)

  Vì có cùng tử số và 2000²⁰¹⁶-2000 < 2000²⁰¹⁶-1 nên \(\frac{2000^{2015}}{2000^{2016}-2000}>\frac{2000^{2015}}{2000^{2016}-1}\)

nên A>B

Answer 2

Xét A trước ta có

2000A=2000.2000^2014/2000^2015-1

2000A=2000^2015-1+1999/2000^2015-1

2000A=1+1999/2000^2015-1

2000B=2000^2015.2000/2000^2016-1

2000B=2000^2016-1+1999/2000^2016-1

2000B=1+1999/2000^2016-1

Ta thấy 2000A>2000B

suy ra A>B