Question

Thực hiện phép tính :

2.\(\sqrt{\dfrac{1}{2}}+\dfrac{1}{\sqrt{2}-1}-\sqrt{8}\)

Answer 1

\(2\sqrt{\dfrac{1}{2}}+\dfrac{1}{\sqrt{2}-1}-\sqrt{8}\)

\(=\sqrt{2}+\sqrt{2}+1-2\sqrt{2}\)

=1

Answer 2

\(2\cdot\sqrt{\dfrac{1}{2}}+\dfrac{1}{\sqrt{2}-1}-\sqrt{8}\)

\(=\dfrac{2}{\sqrt{2}}+\dfrac{\sqrt{2}+1}{2-1}-2\sqrt{2}\)

\(=\sqrt{2}+\sqrt{2}+1-2\sqrt{2}=1\)