$$\frac{1}{2\sqrt{\frac{1}{2}}}=\frac{1}{\sqrt{4}\sqrt{\frac{1}{2}}}=\frac{1}{\sqrt{\frac{4}{2}}}=\frac{1}{\sqrt{2}}$$ Now you can multiply by "1": $$\frac{1}{\sqrt{2}}\frac{1}{1}=\frac{1}{\sqrt{2}} \frac{\sqrt{2}}{\sqrt{2}}=\frac{\sqrt{2}}{(\sqrt{2})^2}=\frac{\sqrt{2}}{2}$$