Question

、在数列中{an}中,已知a1=1,a2=5,a(n+2)=a(n+1)-an,则a2010

有过程，追加财富

Answer 1

a(1)=1,
a(2)=5,
a(3)=4,
a(4)=-1,
a(5)=-5,
a(6)=-4,
a(7)=1,
a(8)=5,
...
a(6n-5)=1,
a(6n-4)=5,
a(6n-3)=4,
a(6n-2)=-1,
a(6n-1)=-5,
a(6n)=-4.
...
a(2010)=a(6*335)=-4

Answer 2

a1=1
a2=5
a3=a2-a1=4
a4=a3-a2=-1
a5=a4-a3=-5
a6=a5-a4=-4
a7=a6-a5=1
a8=a7-a6=5
,
,
,
a2010=-4