\(=\sqrt{\left(2+\sqrt{3}\right)\cdot\left(2-\sqrt{3}\right)}\)
\(=\sqrt{\left(2^2-\left(\sqrt{3}\right)^2\right)}\)
\(=\sqrt{\left(4-3\right)}=1\)
\(\sqrt{2+\sqrt{3}}.\sqrt{2-\sqrt{3}}\)
\(=\) \(\left(\sqrt{2}\right)^2-\left(\sqrt{\sqrt{3}}\right)^2\)
\(\sqrt{2+\sqrt{3}}\cdot\sqrt{2-\sqrt{3}}=\sqrt{4-3}=1\)