\(B=\sqrt{2}+\sqrt{6}+\sqrt{12}+\sqrt{20}+\sqrt{30}+\sqrt{42}+\sqrt{56}+\sqrt{72}+\sqrt{90}+\sqrt{110}\)
\(< \sqrt{2,25}+\sqrt{6,25}+\sqrt{12,25}+\sqrt{20,25}+\sqrt{30,25}+\sqrt{42,25}+\sqrt{56,25}+\sqrt{72,25}+\sqrt{90,25}+\sqrt{110,25}\)
\(=\dfrac{3}{2}+\dfrac{5}{2}+\dfrac{7}{2}+\dfrac{9}{2}+\dfrac{11}{2}+\dfrac{13}{2}+\dfrac{15}{2}+\dfrac{17}{2}+\dfrac{19}{2}+\dfrac{21}{2}\)
\(=\dfrac{3+5+7+9+11+13+15+17+19+21}{2}\)
\(=\dfrac{120}{2}=60\)
Vậy \(B< 60\).
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