Question

So sánh giúp mình với 😥 

Answer 1

\(A=\dfrac{2}{\sqrt{17}+\sqrt{19}}\) ; \(B=\dfrac{2}{\sqrt{19}+\sqrt{21}}\)

Mà \(0< \sqrt{17}+\sqrt{19}< \sqrt{19}+\sqrt{21}\)

\(\Rightarrow\dfrac{2}{\sqrt{17}+\sqrt{19}}>\dfrac{2}{\sqrt{19}+\sqrt{21}}\)

\(\Rightarrow A>B\)