Đáp án:
\(\begin{array}{l}
a)\dfrac{{\sqrt 6 }}{3}\\
b)\dfrac{{\sqrt 5 }}{{60}}\\
c)\dfrac{{\sqrt 6 }}{{14}}\\
d)\dfrac{{\sqrt {21} }}{{70}}
\end{array}\)
Giải thích các bước giải:
\(\begin{array}{l}
a)\sqrt {\dfrac{2}{3}} = \dfrac{{\sqrt {2.3} }}{3} = \dfrac{{\sqrt 6 }}{3}\\
b)\sqrt {\dfrac{1}{{720}}} = \dfrac{1}{{12\sqrt 5 }} = \dfrac{{\sqrt 5 }}{{12.5}} = \dfrac{{\sqrt 5 }}{{60}}\\
c)\sqrt {\dfrac{3}{{98}}} = \dfrac{{\sqrt 3 }}{{7\sqrt 2 }} = \dfrac{{\sqrt {3.2} }}{{7.2}} = \dfrac{{\sqrt 6 }}{{14}}\\
d)\sqrt {\dfrac{3}{{700}}} = \dfrac{{\sqrt 3 }}{{10\sqrt 7 }} = \dfrac{{\sqrt {3.7} }}{{10.7}} = \dfrac{{\sqrt {21} }}{{70}}
\end{array}\)
