Răspuns :
U(2017^2019)=U(7^2019)
u(7^1)=7
u(7^2)=9
u(7^3)=3
u(7^4)=1
deci 2019:4=504 rest 3, u(7^2019)=u(7^3)=3
^ inseamna la puterea, 7^3 inseamna 7 la puterea 3
u(7^1)=7
u(7^2)=9
u(7^3)=3
u(7^4)=1
deci 2019:4=504 rest 3, u(7^2019)=u(7^3)=3
^ inseamna la puterea, 7^3 inseamna 7 la puterea 3