Răspuns :
[tex] \sqrt{1+2+....+2015+2015*1007}= \sqrt{2015*2016/2+2015*1007} = [/tex]
[tex] \sqrt{2015*1008+2015*1007}= \sqrt{2015(1008+1007)} = [/tex][tex] \sqrt{2015*2015}= \sqrt{ 2015^{2} } =2015[/tex]
2015 este numar rational.
[tex] \sqrt{2015*1008+2015*1007}= \sqrt{2015(1008+1007)} = [/tex][tex] \sqrt{2015*2015}= \sqrt{ 2015^{2} } =2015[/tex]
2015 este numar rational.