已知数列an满足a(n+1)=1-1/an且a1=2则a2015=A.1B.-1/2c.3/2D.1/2

Question

已知数列an满足a(n+1)=1-1/an且a1=2则a2015=
A.1 B.-1/2 c.3/2 D.1/2

Answer 1

答案为D,1/2
a1=2,a2=1/2,a3=-1
a4=2,a5=1/2,a6=-1
.
a2014=2,a2015=1/2
n除以3,整除时为an=-1,余数为1时an=2,余数为2时an=1/2