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 ~ 

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

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

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.

\(\sqrt{12}<\sqrt{12,25}=3,5\)

\(\sqrt{20}<\sqrt{20,25}=4,5\)

\(\sqrt{30}<\sqrt{30,25}=5,5\)

\(\sqrt{42}<\sqrt{42,25}=6,5\)

Suy ra:\(\sqrt{12}+\sqrt{20}+\sqrt{30}+\sqrt{42}\)<3,5+4,5+5,5+6,5=20

Vậy biểu thức <20

\(\sqrt{12}+\sqrt{20}+\sqrt{30}+\sqrt{42}

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

ban viet chu mau trang à?

A < B

A  <  20

học tốt

Ta thấy :

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

\(\Rightarrow A< 20\)

Vậy A < 20

~Study well~

#KSJ