Question

Expand f(z)=

$$Expand f(z)= 𝑧+3𝑧(𝑧2−𝑧−2) in power of z where a) |𝑧| < 1 b) 1< |𝑧| < 2 c) |𝑧| > 2$$

𝑧+3 𝑧(𝑧 2−𝑧−2) in power of z where a) |𝑧| < 1 b) 1< |𝑧| < 2 c) |𝑧| > 2