Question

... Упростите выражение:
1)$\sqrt{4 + \sqrt{7} }$
2) $\sqrt{5 + 2 \sqrt{6} }$
3) $\sqrt{8 - 2 \]{ \sqrt{15} } }$
С решением :)​

Answer 1

$1)\sqrt{4+\sqrt{7} } =\sqrt{3,5+\sqrt{7}+0,5 }=\sqrt{(\sqrt{3,5})^{2}+2*\sqrt{3,5}*\sqrt{0,5}+(\sqrt{0,5})^{2}} =\\\\=\sqrt{(\sqrt{3,5}+\sqrt{0,5})^{2}}=\boxed{\sqrt{3,5}+\sqrt{0,5}}\\\\\\2)\sqrt{5+2\sqrt{6} } =\sqrt{3+2\sqrt{6} +2} =\sqrt{(\sqrt{3} )^{2}+2+\sqrt{3}+\sqrt{2}+(\sqrt{2} )^{2}} =\\\\=\sqrt{(\sqrt{3}+\sqrt{2})^{2}}=\boxed{\sqrt{3} +\sqrt{2}}$

$\sqrt{8-2\sqrt{15} }= \sqrt{5-2\sqrt{15}+3 }=\sqrt{(\sqrt{5})^{2} -2*\sqrt{5}*\sqrt{3}+(\sqrt{3})^{2}} =\\\\=\sqrt{(\sqrt{5} -\sqrt{3})^{2}}=|\sqrt{5} -\sqrt{3} |=\boxed{\sqrt{5} -\sqrt{3}}$