Question

Am nevoie de rezolvarea la acest exercițiu.Dau coroană.​

Answer 1

Răspuns:

Explicație pas cu pas:

$A=\frac{1}{\sqrt{3} }+ \frac{2}{\sqrt{3} }+\frac{\sqrt{5} }{\sqrt{3}*\sqrt{5}}= \frac{1}{\sqrt{3} }+ \frac{2}{\sqrt{3} }+\frac{1}{\sqrt{3} }=\frac{4}{\sqrt{3} }=\frac{4\sqrt{3} }{3}\\\\B=\frac{\sqrt{7}+\sqrt{5}}{\sqrt{3}*\sqrt{7}+\sqrt{3}*\sqrt{5}}=\frac{\sqrt{7}+\sqrt{5}}{\sqrt{3}*(\sqrt{7}+\sqrt{5})}=\frac{1}{\sqrt{3} } =\frac{\sqrt{3} }{3}\\\frac{A+B}{\sqrt{3} } =(A+B):\sqrt{3}=(A+B)*\frac{1}{\sqrt{3} }=( \frac{4\sqrt{3} }{3}+\frac{\sqrt{3} }{3})*\frac{1}{\sqrt{3} }=$

$=\frac{5\sqrt{3} }{3}*\frac{1}{\sqrt{3} }=\frac{5}{3}$

Deci 5/3 ∈Q.

A/B=(4√3/3):(√3 /3)=(4√3/3)*(3 /√3)=4∈Z