Giải thích các bước giải:
b.Ta có:
$A=\dfrac{(2+\sqrt{3})\sqrt{2-\sqrt{3}}}{\sqrt{2+\sqrt{3}}}$
$\to A=(2+\sqrt{3})\cdot \dfrac{\sqrt{2-\sqrt{3}}}{\sqrt{2+\sqrt{3}}}$
$\to A=(2+\sqrt{3})\cdot \sqrt{\dfrac{2-\sqrt{3}}{2+\sqrt{3}}}$
$\to A=(2+\sqrt{3})\cdot \sqrt{\dfrac{(2-\sqrt{3})^2}{(2-\sqrt{3})(2+\sqrt{3})}}$
$\to A=(2+\sqrt{3})\cdot \sqrt{\dfrac{(2-\sqrt{3})^2}{2^2-3}}$
$\to A=(2+\sqrt{3})\cdot \sqrt{\dfrac{(2-\sqrt{3})^2}{1}}$
$\to A=(2+\sqrt{3})\cdot \sqrt{(2-\sqrt{3})^2}$
$\to A=(2+\sqrt{3})\cdot (2-\sqrt{3})$
$\to A=2^2-3$
$\to A=1$
