[tex]a)a=(1+2+3+..+2016)^{1+2+3+...+2015}\\
a=(\frac {2016*2017}2})^{\frac{2015*2016}{2}}\\
a=20133136^{2031120}\\
Toate\ puterile\ lui\ 6\ au\ ultime\ cifra\ 6\, deci\ ultima\ cifra\ este\ 6.\\
[/tex]
[tex]b)a=(1008*2017)^{2015*1008}\\
a=[(1008*2007)^{2015}]^{1008}\\
a=\{[(2023056)^{2015}]^{504}\}^{2}=\ \textgreater \ a\ este\ patrat\ perfect.[/tex]