Question

Stabiliti  care dintre  numerele urm sunt rationale:

a.(-2)^-4
b.rad5 supra rad11 totul la puterea -2
c.2rad3supra3 totul la put -3
d.rad6 la put -2
e.2rad2totu la put -3

Answer 1

a) $(-2)^{-4}= \frac{1}{2^4} = \frac{1}{16} \in \ Q$
b)$( \frac{\sqrt{5}}{\sqrt{11}} )^{-2}=( \frac{\sqrt{11}}{\sqrt{5}} )^{2}= \frac{11}{5} \in Q$
c)$( \frac{2 \sqrt{3} }{3})^{-3} =( \frac{3 }{2 \sqrt{3}})^{3}= \frac{27}{ 24\sqrt{3} } = \frac{3 \sqrt{3} }{8} \notin Q$
d) $\sqrt{6} ^{-2}= \frac{1}{ \sqrt{6} ^2} = \frac{1}{6} \in Q$
e)$(2 \sqrt{2} )^{-3}= \frac{1}{(2 \sqrt{2} )^{3}} = \frac{1}{16 \sqrt{2} } = \frac{ \sqrt{2}} {32} \notin Q$