Question

Aratati ca nr. A=2000 la puterea 0 + 2001 la puterea 1 + 2002 la puterea 2 + 2003 la puterea 3 + 2004 la puterea 4 + 1. Aflati daca acest nr este multiplu de 10

Answer 1

 [tex]u(A)=u(2000^0)+u(2001^1)+u(2002^2)+u(2003^3)+u(2004^4)+u(1)\\ u(A)=u(1+1+4+7+6+1)=u(20)=0\;\;\Rightarrow\;\;A\,\vdots\,10\;\;\;adica\;\;\;A=M_{10}[/tex]