Question

SO SÁNH 

a.\(\sqrt{31}\)+ 4 và 6 + \(\sqrt{17}\)

b.\(\sqrt{3}\)+ \(\sqrt{2}\)và  2

c.\(\sqrt{12+13}\)và  \(\sqrt{12}\)+ \(\sqrt{13}\)

Answer 1

a ) 

\(\sqrt{31}+4< \sqrt{36}+4=10\left(1\right)\)

\(6+\sqrt{17}>6+\sqrt{16}=6+4=10\left(2\right)\)

Từ ( 1 ) ; ( 2 ) 

\(\Rightarrow\sqrt{31}+4< 10< 6+\sqrt{17}\)

\(\Rightarrow\sqrt{31}+4< \sqrt{17}+6\)

b ) 

\(\sqrt{3}+\sqrt{2}>\sqrt{1}+\sqrt{1}=2\)

c ) 

\(\sqrt{12+13}=\sqrt{25}=5\left(1\right)\)

\(\sqrt{12}+\sqrt{13}>\sqrt{4}+\sqrt{9}=2+3=5\left(2\right)\)

Từ ( 1 ) ; ( 2 ) 

\(\Rightarrow\sqrt{12+13}< \sqrt{12}+\sqrt{13}\)

Answer 2

:V

khó vc