Tính:
\(\sqrt{10+\sqrt{24}+\sqrt{40}+\sqrt{60}}\)
Tính \(G=\sqrt{10+\sqrt{24}+\sqrt{40}+\sqrt{60}}-\sqrt{16+\sqrt{60}+\sqrt{96}+\sqrt{160}}\)
Chứng minh: \(\sqrt{10+\sqrt{60}+\sqrt{24}+\sqrt{40}}=\sqrt{5}+\sqrt{3}+\sqrt{2}\)
\(10+\sqrt{60}+\sqrt{24}+\sqrt{40}=10+2\sqrt{15}+2\sqrt{6}+2\sqrt{10}\)
\(=\left(5+2\sqrt{15}+3\right)+2+2\sqrt{2}\left(\sqrt{5}+\sqrt{3}\right)\)
\(=\left(\sqrt{5}+\sqrt{3}\right)^2+2\sqrt{2}\left(\sqrt{5}+\sqrt{3}\right)+2\)
\(=\left(\sqrt{5}+\sqrt{3}+\sqrt{2}\right)^2\)
\(\Rightarrow\sqrt{10+\sqrt{60}+\sqrt{24}+\sqrt{40}}=\sqrt{5}+\sqrt{3}+\sqrt{2}\)
Dùng hẳng đẳng thức 3 số:
$(a+b+c)^2=a^2+b^2+c^2+2ab+2bc+2ca$
$VT=\sqrt{5+3+2+2\sqrt{15}+2\sqrt{6}+2\sqrt{10}}=\sqrt{(\sqrt5+\sqrt3+\sqrt2)^2}=VP(đpcm)$
\(\sqrt{10+\sqrt{60}-\sqrt{24}-\sqrt{40}}-\sqrt{3}-\sqrt{5}+2\)
CMR:\(\sqrt{10+\sqrt{24}+\sqrt{40}+\sqrt{60}}=\sqrt{2}+\sqrt{3}+\sqrt{5}\)
\(\sqrt{10+\sqrt{24}+\sqrt{40}+\sqrt{60}}=\sqrt{2+3+5+2\sqrt{2.3}+2\sqrt{2.5}+2\sqrt{3.5}}\)
\(=\sqrt{\left(\sqrt{2}+\sqrt{3}+\sqrt{5}\right)^2}=\sqrt{2}+\sqrt{3}+\sqrt{5}\)
\(\sqrt{10+\sqrt{24}+\sqrt{40}+\sqrt{60}}\)
\(\sqrt{10+\sqrt{24}+\sqrt{40}+\sqrt{60}}\)
\(\sqrt{10+\sqrt{24}+\sqrt{40}+\sqrt{60}}\)
\(=\sqrt{10+\sqrt{25-1}+\sqrt{49-9}+\sqrt{64-4}}\)
\(=\sqrt{10+\sqrt{5^2-1^2}+\sqrt{7^2-3^2}+\sqrt{8^2-2^2}}\)
\(=\sqrt{10+\left(\sqrt{5-1}\right)^2+\left(\sqrt{7-3}\right)^2+\left(\sqrt{8-2}\right)^2}\)
\(=\sqrt{10+5-1+7-3+8-2}\)
\(=\sqrt{24}\)
\(=2\sqrt{6}\)
\(\sqrt{10+\sqrt{24}+\sqrt{40}+\sqrt{60}}\)
bye mình đi ngủ đây chúc bạn ngủ ngon. bài này dễ lắm.
\(\sqrt{10+\sqrt{24}+\sqrt{40}+\sqrt{60}}\)
\(=\sqrt{10+2\sqrt{6}+2\sqrt{10}+2\sqrt{15}}\)
\(=\sqrt{\left(\sqrt{2}+\sqrt{5}+\sqrt{3}\right)^2}\)
\(=\sqrt{2}+\sqrt{3}+\sqrt{5}\)
\(\sqrt{10+\sqrt{24}+\sqrt{40}+\sqrt{60}}=\sqrt{10+2.\sqrt{6}+2.\sqrt{10}+2.\sqrt{15}}\)
\(=\sqrt{2+3+5+2.\sqrt{2.3}+2.\sqrt{2.5}+2.\sqrt{3.5}}\)
\(=\sqrt{\left(\sqrt{2}+\sqrt{3}+\sqrt{5}\right)^2}=\sqrt{2}+\sqrt{3}+\sqrt{5}\)
C/m : \(\sqrt{10+\sqrt{60}-\sqrt{24}-\sqrt{40}}=\sqrt{3}+\sqrt{5}-\sqrt{2}\)
Muội chả hỉu sao tỷ học giỏi vậy!
Chứng minh
\(\sqrt{10+\sqrt{60}-\sqrt{24}-\sqrt{40}}=\sqrt{3}+\sqrt{5}-\sqrt{2}\)
\(\sqrt{10+\sqrt{60}-\sqrt{24}-\sqrt{40}}\)
\(=\sqrt{2+3+5+2\sqrt{6}+2\sqrt{10}+2\sqrt{15}}\)
\(=\left(\sqrt{3}+\sqrt{5}-\sqrt{2}\right)^2\)
\(=\sqrt{3}+\sqrt{5}-\sqrt{2}\)