Răspuns:
Explicație pas cu pas:
U(71^10000001) = U(1^10000001) = 1
___________
U(1009^9001) = U(9^9001)
U(9^1) = 9
U(9^2) = 1
U(9^3) = 9
9 la putere impara se termina in 9
U(1009^9001) = 9
___________
77^36 + 77^37 + 77^38 + 77^39
= 77^36*(1 + 7 + 7^2 + 7^3)
= 77^36*(1 + 7 + 49 + 343)
= 400*77^36 se termina in 0