46. Вычислить: 1) \(\sqrt{9+\sqrt{17}}\cdot\sqrt{9-\sqrt{17}}\); 2) \((\sqrt{3+\sqrt5}-\sqrt{3-\sqrt5})^2\); 3) \((\sqrt{5+\sqrt{21}}+\sqrt{5-\sqrt{21}})^2\).

1. \(\sqrt{(9+\sqrt{17})(9-\sqrt{17})}=\sqrt{81-17}=\sqrt{64}=8\).
2. \(6-2\sqrt{(3+\sqrt5)(3-\sqrt5)}=6-2\sqrt4=2\).
3. \(10+2\sqrt{(5+\sqrt{21})(5-\sqrt{21})}=10+2\sqrt4=14\).

Ответ: 1) \(8\); 2) \(2\); 3) \(14\).