1, let x=t+2, because f(x+2)=-f(x), then -f(x+2)=f(x), so f ((t+2)+2) =-f (t).
2. When x=0,
When f(x)=0 and x=4, in terms of periodicity, f (x) = 0; If f(x) is odd function, it is-1≤x≤ 1, and f (x) =1&; Like chopping a wet raft and splashing # 47; Add the above conditions to get 2x, x ∈ [1, 3], f(x)=- 1/2x.