Complex analysis: mapping a hyperbola onto a line

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SUMMARY

The discussion focuses on creating a one-to-one, conformal mapping from the right side of the hyperbola defined by the equation x² - y² = 1 onto the line v = 0, while mapping points to the left of the hyperbola above this line. The proposed mapping utilizes complex variables, specifically defining x and y in terms of z = x + iy, leading to the equations u = y and v = y² - x² + 1. The challenge lies in ensuring that all points on the left side of the y-axis are correctly mapped above the line v = 0, which necessitates further exploration of the Cauchy-Riemann equations to determine the appropriate function f(z).

PREREQUISITES
  • Understanding of hyperbolas and their equations, specifically x² - y² = 1.
  • Familiarity with complex variables and functions, particularly z = x + iy.
  • Knowledge of conformal mappings and their properties.
  • Basic understanding of the Cauchy-Riemann equations in complex analysis.
NEXT STEPS
  • Study the Cauchy-Riemann equations to derive the function u(x,y) for the mapping.
  • Explore conformal mapping techniques in complex analysis to understand their applications.
  • Investigate methods to disregard specific regions in mappings, particularly for hyperbolas.
  • Practice mapping techniques using different hyperbolic equations and their transformations.
USEFUL FOR

Students and professionals in mathematics, particularly those focused on complex analysis, geometric transformations, and conformal mappings. This discussion is beneficial for anyone seeking to deepen their understanding of hyperbolic functions and their applications in mapping.

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Homework Statement



We want to create a map from (x,y) to (u,v) such that the right side (positive x) of the hyperbola x^2 - y^2 = 1 is mapped onto the line v = 0 AND all the points to the left of that hyperbola are mapped to above the line. The mapping should be one-to-one and conformal


Homework Equations



I think (but am not 100% sure) the map has to be from z = x+iy to w = u+iv, so it's important to define x and y in terms of z. I figured out that x = (z+conj(z))/2 and y = (z-conj(z))/2

The Attempt at a Solution



We can map y directly to u through u = y. That should be sufficient I think.
v = x^2 - y^2 - 1 does map the parabola onto the line (it makes v = 0) but it maps the points to the right of the parabola onto above the line, so we multiply by -1 to get v = y^2 - x^2 + 1. We can write everything as:

w = y + i(y^2 - x^2 + 1) and then substitute the x = (z+conj(z))/2 and y = (z-conj(z))/2 into make it a function of z.

This seems to work for when x >= 0, but it fails to map some points on the left side of the y-axis (all of which should be mapped to above the line v = 0). This is because the function x^2 - y^2 = 1 describes two parabolas, and we have to somehow mathematically disregard the left one. I'm not sure how to do that. Could somebody please help?
 
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You aren't really dealing with this as a complex function yet. You have got that v(x,y)=x^2-y^2-1 if f(z)=u(x,y)+i*v(x,y) where z=x+iy.That's a start. Now shouldn't you think about using the Cauchy-Riemann equations to figure out what u(x,y) might be and then try to deduce what f(z) might be?
 

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