\(A=\sqrt{6}+\sqrt{12}+\sqrt{30}+\sqrt{56}\)

\(B^2=\left(\sqrt{6}+\sqrt{30}\right)^2=36+2\sqrt{180}>36+26=62\)

B>7;\(\sqrt{30}>5;\sqrt{56}>7\)

A>7+5+7=19

A>19

19 bé hơn

19 lớn hơn hoặc bằng

\(19=2,5+3,5+5,5+7,5\)

       \(=\sqrt{6,25}+\sqrt{12,25}+\sqrt{30,25}+\sqrt{56,25}\)

     > √6     + √12      + √30    + √56     

\(\sqrt{2}+\sqrt{6}+\sqrt{12}+...+\sqrt{110}\)\(=\sqrt{1.2}+\sqrt{2.3}+\sqrt{3.4}+...+\sqrt{10.11}\)

\(< \frac{1+2}{2}+\frac{2+3}{2}+\frac{3+4}{2}+...+\frac{10+11}{2}\)\(=\frac{1}{2}\left[\left(1+2+3+...+10\right)+\left(2+3+4+...+11\right)\right]\)\(=\frac{1}{2}\left(\frac{11.10}{2}+\frac{13.10}{2}\right)=\frac{1}{2}\left(55+65\right)=60\)

Vậy \(\sqrt{2}+\sqrt{6}+\sqrt{12}+...+\sqrt{110}< 60.\)

chị ơi toán lớp 7 hả

\(\sqrt{2}+\sqrt{6}+\sqrt{12}+\sqrt{20}+\sqrt{30}+\sqrt{42}+\sqrt{56}+\sqrt{72}+\sqrt{90}+\sqrt{110}\) < 60 nha.

ghi de sai ban oi

\(A=\sqrt{2}+\sqrt{6}+\sqrt{12}+\sqrt{20}+\sqrt{30}+\sqrt{42}\)

\(A< \sqrt{2,25}+\sqrt{6,25}+\sqrt{12,25}+\sqrt{20,25}+\sqrt{30,25}+\sqrt{42,25}=24=B\)

Vậy \(A< B\)

Chúc bạn học tốt ~ 

A=√2+√6+√12+√20+√30+√42

A= 23.7579

B= 24

vậy => B > A

giúp mk với

A=√2+√6+√12+√20+√30+√42

A=23,75790715

Mà B=24

=>A<B