68. Вычислить: 1) \(2^{\sqrt5}\cdot2^{-\sqrt5}\); 2) \(3^{\sqrt2}:9^{\sqrt2}\); 3) \((5^{\sqrt3})^{\sqrt3}\); 4) \(((0.5)^{\sqrt2})^{\sqrt8}\).

1. \(2^{\sqrt5-\sqrt5}=2^0=1\).
2. \(3^{\sqrt2}:3^{2\sqrt2}=3^{-\sqrt2}=\frac1{3^{\sqrt2}}\).
3. \(5^{\sqrt3\cdot\sqrt3}=5^3=125\).
4. \((0.5)^{\sqrt2\cdot\sqrt8}=(0.5)^4=\frac1{16}\).

Ответ: 1) 1; 2) \(3^{-\sqrt2}\); 3) 125; 4) \(\frac1{16}\).