Conversion of parametric form to polar for the rose curve

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Discussion Overview

The discussion focuses on the conversion of the parametric form of the Rhodonea curve, also known as the rose curve, to its polar form. Participants explore the relationship between the given polar equation and its parametric representation, seeking clarity on the conversion process and the derivation of rectangular coordinates.

Discussion Character

  • Exploratory
  • Technical explanation
  • Mathematical reasoning

Main Points Raised

  • One participant presents the polar equation r = cos(k) and the parametric equations as x = cos(k(theta)) cos(theta) and y = cos(k(theta)) sin(theta), requesting a detailed conversion process.
  • Another participant notes that there is something missing in the provided parametric equations and suggests that x and y can be expressed as functions of k, indicating that various monotonous functions could serve as valid parametrizations.
  • A later reply reiterates the point about the non-uniqueness of parametric descriptions, emphasizing that multiple valid parametrizations exist.
  • One participant provides the equations x = r cos(theta) and y = r sin(theta), stating that either equation can lead to the polar equation and that r can be isolated through cancellation.

Areas of Agreement / Disagreement

Participants express uncertainty regarding the completeness of the parametric equations and the conversion process. There is no consensus on a single method for the conversion, and multiple viewpoints on parametrization are presented.

Contextual Notes

Some participants indicate that the parametric descriptions may not be unique and that additional assumptions or definitions may be necessary for a complete understanding of the conversion process.

Alphonso2001
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Hi,

The main question revolves around the Rhodonea curve AKA rose curve. The polar equation given for the curve is r=cos(k). The parametric equation is = cos(k(theta)) cos (theta), = cos(k(theta)) sin(theta) . Can anyone show me the conversion from the general parametric form to the general polar form. Basically what I am looking for is the working. How did the parametric form get converted to polar?P.S. In the case that the aforementioned doesn't happen, even if you are able to find the general rectangular coordinate form for the given polar equation above, it will work for meThanks!
 
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Alphonso2001 said:
The parametric equation is = cos cos (), = cos () sin
There is something missing.

You can find x and y as function of k, this gives you a natural parametrization. Every monotonous function k(t) that covers the same range will work as well, plus a few more exotic examples.

Parametric descriptions are never unique.
 
Hi
mfb said:
There is something missing.

You can find x and y as function of k, this gives you a natural parametrization. Every monotonous function k(t) that covers the same range will work as well, plus a few more exotic examples.

Parametric descriptions are never unique.
My bad. I edited it
 
##x=r\cos(\theta)=\cos(k \theta)\cos(\theta)\\
y=r\sin(\theta)=\cos(k \theta)\sin(\theta)##
either equation gives the polar equation and r can be isolated by cancellation
 

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