Complex Analysis
Complex Analysis
Complex Plane
Polar Coordinates
angle is often called the argument
De Moivre's Formula
Nth Roots
primary::roots unity
We can think of other nth roots as roots of unity corrected for length.
Complex Functions
A complex function is continuous in the complex plane in an analogous way as it is in the reals. Also note, the Extreme Value Theorem holds in the complex plane as it does in the reals: a continuous function on a compact set attains its min\/max.
Nice Properites:
• sum\/product of holomorphic functions is holomorphic
• quotient, f\/g, of holomorphic functions such that g(z_0) ≠ 0, is also holomorphic
The Jacobian of a function f(x, y) is matrix of partial derivatives.
Cauchy Riemann Condition
It turns out a holomorphic function at a point satisfies the Cauchy Riemann Equations:
and
use limits to show this is true with the realization the derivative should be the same regardless of the direction you approach the point with.
Furthermore, if u and v have continuous derivatives (continuously differentiable) and the Cauchy Riemann Equations hold then f is holomorphic (in the open set on which f is defined).
Power Series
[in progress]
Text Reference
Complex Analysis, by Stein and Shakarchi
Other references
A First Course In Complex Analysis, by Beck, Marchesi, Pixton, and Sabalka
Functions of One Complex Variable, by John Conway (used in Course)
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