Let f(x)=exp(−1/x2)f(x) = \exp(-1/x^2)f(x)=exp(−1/x2) for x≠0x \neq 0x=0 and f(0)=0f(0) = 0f(0)=0. What is f′(0)f'(0)f′(0)?
000
111
Does not exist
∞\infty∞