Complex Analysis
Functions of a complex variable -- where differentiability becomes a much stronger, more geometric idea, and a single theorem (Cauchy's) unlocks results no real-variable argument can reach.
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- Chapter overview
- Complex arithmetic, revisited ~12 min
- Polar and exponential form, revisited ~14 min
- De Moivre's theorem and roots of unity, revisited ~14 min
- The Fundamental Theorem of Algebra, revisited ~12 min
- Sequences and series, revisited ~12 min
- Power series and radius of convergence, revisited ~12 min
- Partial derivatives and Green's theorem, revisited ~14 min
- Chapter wrap-up
1 The complex plane π
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- The complex plane and regions ~16 min
- Distance, circles, and disks ~16 min
- Lines, half-planes, and loci ~16 min
- Inequalities and regions ~18 min
- Connectedness and domains ~16 min
2 Complex functions, limits, and continuity π
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- Functions of a complex variable ~16 min
- Limits of complex functions ~18 min
- Limits via real and imaginary parts ~18 min
- Continuity ~16 min
- Limits and the point at infinity ~16 min
3 Complex differentiation and the Cauchy-Riemann equations π
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- The complex derivative ~16 min
- Analytic, holomorphic, and entire functions ~14 min
- The Cauchy-Riemann equations β necessary conditions ~18 min
- The Cauchy-Riemann equations β sufficient conditions ~16 min
- Cauchy-Riemann in polar coordinates ~15 min
- Zero derivative implies constant ~14 min
4 Harmonic functions π
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- Harmonic functions and Laplace's equation ~16 min
- Harmonic conjugates ~18 min
- The maximum principle and mean value property ~16 min
- The identity theorem ~16 min
- The Schwarz reflection principle ~15 min
5 Elementary Complex Functions π
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- The complex exponential function ~20 min
- The logarithm and its branches ~22 min
- Complex powers ~20 min
- Trigonometric and hyperbolic functions ~22 min
- Inverse trigonometric and hyperbolic functions ~20 min
6 Complex Integration π
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- Contours and parametrization ~20 min
- Contour integrals ~25 min
- Properties of contour integrals and the ML inequality ~25 min
- Antiderivatives and path independence ~25 min
- The fundamental theorem for contour integrals ~20 min
7 Cauchy's Theorem and Its Consequences π
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- The Cauchy-Goursat theorem ~24 min
- Simply and multiply connected domains ~20 min
- Contour deformation ~20 min
- The Cauchy integral formula ~24 min
- The derivative formula ~22 min
- Liouville's theorem and the Fundamental Theorem of Algebra ~22 min
- The maximum modulus principle ~22 min
8 Power Series and Taylor Series π
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- Convergence of complex sequences and series ~22 min
- Taylor's theorem for analytic functions ~22 min
- Uniform convergence and term-by-term calculus ~20 min
- Uniqueness of power series representations ~18 min
- Multiplying and dividing power series ~20 min
9 Laurent Series and Singularities π
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- Laurent's theorem ~24 min
- Isolated singularities -- removable, pole, and essential ~24 min
- The pole order and residue shortcut formula ~24 min
- Zeros of analytic functions ~22 min
- Behavior near isolated singularities ~22 min
10 The Residue Theorem π
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- The residue ~20 min
- Cauchy's residue theorem ~22 min
- Residue at infinity ~20 min
- Computing residues, several methods ~22 min
11 Applications of Residues π
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- Real improper integrals via semicircular contours ~24 min
- Trigonometric integrals via the unit circle ~22 min
- Indented contours and principal values ~24 min
- Jordan's lemma ~24 min
- The argument principle ~24 min
- RouchΓ©'s theorem ~26 min
- Inverse Laplace transforms via residues ~26 min
12 Mobius Transformations and Conformal Mapping π
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- Linear transformations and inversion ~18 min
- MΓΆbius transformations ~20 min
- Conformal mapping and angle preservation ~18 min
- The elementary mapping catalogue ~18 min
- The Riemann sphere and the extended complex plane ~18 min
- Schwarz's lemma ~18 min
- The Schwarz-Pick theorem ~20 min
- Harmonic conjugates revisited ~20 min
13 Applications of Conformal Mapping π
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- Steady-state temperature and electrostatic potential ~24 min
- Two-dimensional fluid flow ~24 min
- The Schwarz-Christoffel transformation ~26 min
- The Poisson integral formula and the Dirichlet problem ~28 min
- The Neumann problem ~20 min
14 Analytic Continuation π
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- Natural boundaries ~20 min
- The identity theorem, revisited ~18 min
- Continuation along a curve ~20 min
- Branch points and why continuation can fail ~20 min
15 Advanced Topics: The Gamma Function and Complex Dynamics π
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- The Gamma function ~22 min
- The functional equation and the reflection formula ~24 min
- An introduction to complex dynamics ~20 min
- Julia sets and the Mandelbrot set, qualitatively ~22 min