[tex]14.\\\frac{1}{\sqrt2}=\frac{1}{\sqrt2}\cdot\frac{\sqrt2}{\sqrt2}=\frac{\sqrt2}{2}\\\\15.\\\\\sqrt{3\cdot3\cdot4\cdot5\cdot5\cdot4}=\sqrt{3^2\cdot4^2\cdot5^2}=3\cdot4\cdot5=60[/tex]
