Question

So sánh : \(\sqrt{\dfrac{16}{25}}\) và \(\dfrac{\sqrt{16}}{\sqrt{25}}\).

Answer 1

Ta có: \(\sqrt {\frac{{16}}{{25}}}  = \sqrt {{{\left( {\frac{4}{5}} \right)}^2}}  = \frac{4}{5}\)

\(\frac{{\sqrt {16} }}{{\sqrt {25} }} = \frac{{\sqrt {4{}^2} }}{{\sqrt {{5^2}} }} = \frac{4}{5}\).

Vậy \(\sqrt {\frac{{16}}{{25}}}  = \frac{{\sqrt {16} }}{{\sqrt {25} }}\).