u([tex] 2^{1} [/tex])= 2
u([tex] 2^{2} [/tex])=4
u([tex] 2^{3} [/tex])= 8
u([tex] 2^{4} [/tex])=..6
u([tex] 2^{5} [/tex])=..2
...
=> ca ultimele cifre se repeta in grupe de cate patru (2,4,8,6,...2,4,8,6)
=> 2010:4=502 rest 2 => u([tex] 2^{2010} [/tex])=.4