Define f ∶ \(\mathbb{C} \rightarrow \mathbb{C}\) by f(z) = ||z|2 -.1|2. Which of the following statements is true?
1
f is complex differentiable at all complex numbers except for z ∈ {0, 1}
2
f is complex differentiable only at z = 0
3
f is complex differentiable only at z = 1
4
f is complex differentiable only for z ∈ {0, 1}