Paper 3, Section II, F

Complex Analysis
Part IB, 2019

Define the winding number n(γ,w)n(\gamma, w) of a closed path γ:[a,b]C\gamma:[a, b] \rightarrow \mathbb{C} around a point wCw \in \mathbb{C} which does not lie on the image of γ\gamma. [You do not need to justify its existence.]

If ff is a meromorphic function, define the order of a zero z0z_{0} of ff and of a pole w0w_{0} of ff. State the Argument Principle, and explain how it can be deduced from the Residue Theorem.

How many roots of the polynomial

z4+10z3+4z2+10z+5z^{4}+10 z^{3}+4 z^{2}+10 z+5

lie in the right-hand half plane?