If f(x)=x2+1f(x) = x^2 + 1f(x)=x2+1 for x>0x > 0x>0 and f(x)=2xf(x) = 2xf(x)=2x for x≤0x \le 0x≤0, find f(f(−1))f(f(-1))f(f(−1)).
-4
-2
5
1