11.4 If $\sqrt{3-2 \sqrt{2}}=\sqrt{c}-\sqrt{d}$, find the value of $d$.
Reference: 1999 HG3, 2001 FG2.1, 2011 HI7, 2015 FI4.2, 2015 FG3.1
$$
\begin{aligned}
\sqrt{3-2 \sqrt{2}} & =\sqrt{1-2 \sqrt{2}+2} \\
& =\sqrt{(\sqrt{1})^{2}-2 \sqrt{2}+(\sqrt{2})^{2}} \\
& =\sqrt{(\sqrt{2}-1)^{2}}=\sqrt{2}-1 \\
\Rightarrow d=1 &
\end{aligned}
$$