Proving Homeomorphism for Stereographic Projection onto S1-{(1, 0)}

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SUMMARY

The discussion focuses on proving that the map f : R--> S1 defined by f(t) = [(t^2-1)/(t^2+1), 2t/(t^2+1)] is a homeomorphism onto S1-{(1, 0)}. This map represents a stereographic projection from the real line to the unit circle minus the point (1, 0). Key steps include demonstrating that the map is continuous and establishing the existence of a continuous inverse, which can be approached by expressing the range in polar coordinates.

PREREQUISITES
  • Understanding of stereographic projection
  • Knowledge of homeomorphisms in topology
  • Familiarity with polar and rectangular coordinate systems
  • Basic concepts of continuity in mathematical functions
NEXT STEPS
  • Study the properties of stereographic projections in detail
  • Learn how to demonstrate continuity and the existence of continuous inverses
  • Explore polar coordinate transformations and their applications
  • Investigate the definition and examples of homeomorphisms in topology
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Mathematics students, particularly those studying topology and analysis, as well as educators looking for examples of homeomorphisms and stereographic projections.

guroten
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Homework Statement



Show that the map f : R--> S1 given by f(t) =[(t^2-1)/(t^2+1), 2t/(t^2+1)] is a homeomorphism onto S1-{(1, 0)}, where S1 is the unit circle in the plane.

I know this is a stereographic projection, but I do not know how to show that it has a continuous inverse. I am also unsure how to show it is onto. Any help would be appreciated.
 
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Try expressing the range in polar coordinates rather than rectangular.
 

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