Question

已知函數(shù)f(x)對(duì)應(yīng)關(guān)系如表所示,數(shù)列{a_n}滿足a₁=3,a_n+1=f(a_n),則a₂₀₁₅=________.

x	1	2	3
f(x)	3	2	1

 

Answer 1

3

由題意知a₂=f(a₁)=f(3)=1,a₃=f(a₂)=f(1)=3,a₄=f(a₃)=f(3)=1,
所以數(shù)列{a_n}是周期為2的數(shù)列,
所以a₂₀₁₅=a₁=3.