[tex]a=\frac{\sqrt{2}+1}{2}\\
b=\frac{2}{\sqrt{2}-1}\\
\frac{b}{a}=\frac{2}{\sqrt{2}-1}\cdot\frac{2}{\sqrt{2}+1}=\frac{4}{2-1}=4\\
[/tex]
[tex]\frac{a}{b}=\frac{\sqrt{2}+1}{2}\cdot\frac{\sqrt{2}-1}{2}=\frac{2-1}{4}=\frac{1}{4}\\
\frac{b}{a}-\frac{a}{b}=4-\frac{1}{4}=\frac{16}{4}-\frac{1}{4}=\frac{15}{4}[/tex]