rút gọn
1/\(\sqrt{2+\sqrt{3}}.\sqrt{2+\sqrt{2+\sqrt{3}}}.\sqrt{2-\sqrt{2+\sqrt{3}}}\)
2.\(\sqrt{8-2\sqrt{15}}-\sqrt{8+2\sqrt{15}}\)
so sánh 1/ \(\sqrt{7}-\sqrt{6}với\sqrt{3}-\sqrt{2}\)
2/\(\sqrt{2005}+\sqrt{2007}với2\sqrt{2006}\)
3/\(\sqrt{2+\sqrt{3}}+\sqrt{2-\sqrt{3}}với\sqrt{2}+1\)