#1
|
|||
|
|||
กรณฑ์
จงหาค่าของ $\sqrt{20+7\sqrt{10} }$
|
#2
|
||||
|
||||
$\sqrt{20+7\sqrt{10} }=\sqrt{2\sqrt{10}\sqrt{10}+7\sqrt{10} }=\sqrt{\sqrt{10}(2\sqrt{10}+7) }=\sqrt{\sqrt{10}}\sqrt{7+2\sqrt{10} } =\sqrt[4]{10}(\sqrt{5}+\sqrt{2})= \sqrt[4]{10}(\sqrt[4]{25}+\sqrt[4]{4})=\sqrt[4]{250}+\sqrt[4]{40}$
|
|
|