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Complex Analysis
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1. Complex numbers
- Roots of a complex number
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2. Mappings
- The function f(z)=1/z (Part 1)
- The function f(z)=1/z (Part 2)
- The function f(z)=z/|z|^2
- The function f(z)=sin(z) (Part 1)
- The function f(z)=sin(z) (Part 2)
- The function f(z)=exp(z)
- The function f(z)=log(z) (Part 1)
- The function f(z)=log(z) (Part 2)
- The function f(z)=log(z+1)
- Möbius transformation
- Mapping squares
- Mapping squares
- Mapping squares
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3. Riemann Surfaces
- Riemann Surface: z^(1/2)
- Riemann Surface: log(z)
- Riemann Surface: z^(1/3)
- Riemann Surface: (1-z^2)^(1/2)
- Riemann Surface: arctan(z)
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4. Analytic functions
- Riemann sphere
- Riemann sphere (2nd part)
- Visualising zeros of complex polynomials
- Graphs of complex functions
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5. Series
- Series (Part I)
- Series (Part II)
- The exponential complex function
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6. Applications
- Hydrodynamics: Streamlines and velocity potentials
- Complex potential
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Complex Analysis
Juan Carlos Ponce Campuzano, Doug Kuhlmann, Mar 19, 2018

A visual point of view of different topics related to Complex Analysis
Table of Contents
- Complex numbers
- Roots of a complex number
- Mappings
- The function f(z)=1/z (Part 1)
- The function f(z)=1/z (Part 2)
- The function f(z)=z/|z|^2
- The function f(z)=sin(z) (Part 1)
- The function f(z)=sin(z) (Part 2)
- The function f(z)=exp(z)
- The function f(z)=log(z) (Part 1)
- The function f(z)=log(z) (Part 2)
- The function f(z)=log(z+1)
- Möbius transformation
- Mapping squares
- Mapping squares
- Mapping squares
- Riemann Surfaces
- Riemann Surface: z^(1/2)
- Riemann Surface: log(z)
- Riemann Surface: z^(1/3)
- Riemann Surface: (1-z^2)^(1/2)
- Riemann Surface: arctan(z)
- Analytic functions
- Riemann sphere
- Riemann sphere (2nd part)
- Visualising zeros of complex polynomials
- Graphs of complex functions
- Series
- Series (Part I)
- Series (Part II)
- The exponential complex function
- Applications
- Hydrodynamics: Streamlines and velocity potentials
- Complex potential
Roots of a complex number
To solve the equation for and

Change the values of a, b, and n.
Mappings
Mappings by different functions
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1. The function f(z)=1/z (Part 1)
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2. The function f(z)=1/z (Part 2)
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3. The function f(z)=z/|z|^2
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4. The function f(z)=sin(z) (Part 1)
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5. The function f(z)=sin(z) (Part 2)
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6. The function f(z)=exp(z)
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7. The function f(z)=log(z) (Part 1)
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8. The function f(z)=log(z) (Part 2)
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9. The function f(z)=log(z+1)
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10. Möbius transformation
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11. Mapping squares
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12. Mapping squares
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13. Mapping squares
The function f(z)=1/z (Part 1)
Mapping lines and circles with the function
The function f(z)=1/z (Part 1)


Riemann Surface: z^(1/2)


GGB script
Re1(x, y) = exp(1 / 2 * log( sqrt( x*x + y*y ) ) ) * cos(1 / 2 * arctan2( y, x ))
Im1(x, y) = exp(1 / 2 * log( sqrt( x*x + y*y ) ) ) * sin(1 / 2 * arctan2( y, x ))
t = Slider(0, 1, 0.1, 1, 100, false, true, false, false)
HRe1(x, y) = 0 * (1-t) + Re1(x, y) * t
HIm1(x, y) = 0 * (1-t) + Im1(x, y) * t
Re2(x, y) = exp(1 / 2 * log( sqrt( x * x + y*y ) ) ) * cos(1 / 2 * (arctan2( y, x ) + 2 pi))
Im2(x, y) = exp(1 / 2 * log( sqrt( x * x + y*y ) ) ) * sin(1 / 2 * (arctan2( y, x )+2 pi))
HRe2(x, y) = 0 * (1-t) + Re2(x, y) * t
HIm2(x, y) = 0 * (1-t) + Im2(x, y) * t
RSRe = Surface(u*cos(v), u*sin(v), HRe1(u*cos(v), u*sin(v)), u, 0, 2, v, -pi, pi-pi/200)
RSIm = Surface(u*cos(v), u*sin(v), HIm1(u*cos(v), u*sin(v)), u,0, 2, v, -pi, pi-pi/200)
RSReN = Surface(u*cos(v), u*sin(v), HRe2(u*cos(v), u*sin(v)), u, 0, 2, v, -pi, pi-pi/200)
RSImN = Surface(u*cos(v), u*sin(v), HIm2(u*cos(v), u*sin(v)), u, 0, 2, v, -pi, pi-pi/200)
Riemann sphere
The extended complex plane can be mapped onto the surface of a sphere whose south
pole corresponds to the origin and whose north pole to the point .


Move the slider x and y to move the point
Series (Part I)
An infinite series of complex numbers converges to the sum if the sequence of partial sums converges to . We then write . For example, .
Drag the point around to see what happens to the partial sums when is inside or out of the open ball .
Series (Part I)


Hydrodynamics: Streamlines and velocity potentials
If we have a (steady-state) incompressible, nonviscous fluid, we are interested in finding its velocity field
If is the complex potential, the functions and are the velocity potential and stream functions, respectively. In this case .
Hydrodynamics: Streamlines and velocity potentials


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