[tex]\bf 1.\\ \\ \it1+3+5+\ ...\ +(2n-1)+(2n+1)=625 \Rightarrow (n+1)^2=25^2 \Rightarrow n=24\\ \\ \bf5.\\ \\ \it\overline{u},\ \ \overline v\ coliniari \Rightarrow \dfrac{1}{2}=\dfrac{5}{m} \Rightarrow m=10\\ \\ \\ \overline{v}=2\overline i+10\overline j;\ \ \ |\overline v|=\sqrt{2^2+10^2}=\sqrt{104}=\sqrt{4\cdot26}=2\sqrt{26}[/tex]
6.
[tex]\it \ell_3=R\sqrt3=1\sqrt3=\sqrt3;\ \ \ \mathcal{A}=\dfrac{\ell^2\sqer3}{4}=\dfrac{(\sqrt3)^2\sqrt3}{4}=\dfrac{3\sqrt3}{4}[/tex]
