Paramatize a non-linear curve between points

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Discussion Overview

The discussion revolves around the parametrization of a non-linear curve between two specified points, (1,0) and (a,b). Participants explore various approaches to create a parabolic curve that connects these points, while also addressing the broader concept of non-linear curves between two points.

Discussion Character

  • Exploratory
  • Technical explanation
  • Mathematical reasoning

Main Points Raised

  • One participant suggests starting with a parabolic parametrization but struggles to find a suitable equation that fits the points, proposing y=1-x^2 for x in the range (1,a).
  • Another participant proposes a general form for a parabola, y=Ax²+Bx+C, and outlines a method to determine the coefficients A, B, and C based on the conditions that the curve passes through the given points.
  • A later reply discusses the infinite possibilities of non-linear curves between two points, suggesting a more complex parametrization involving multiple parameters and equations to satisfy the conditions of passing through both points.
  • One participant emphasizes that while there is a unique straight line between any two points, there are infinitely many non-linear curves, indicating the complexity of the problem.

Areas of Agreement / Disagreement

Participants express various methods and approaches to the problem, but no consensus is reached on a single solution or parametrization. Multiple competing views and methods remain present in the discussion.

Contextual Notes

Some participants note the dependence on specific values of a and b, particularly when a=1 or a=0, which may affect the applicability of certain parabolic forms. The discussion also highlights the existence of other potential curves beyond parabolas.

Tom McCurdy
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I was wondering how you could paramatize a non-linear curve between two points (1,0) and (a,b)

I have been trying to do like a parabolic paramatization but I am getting nowhere

I can get the first point alright

x=x
y=1-x^2
1<x<a
but then you get y=1-x^2

Any suggestions
 
Physics news on Phys.org
do you now this?
x*lnx=9
x=?
 
EDIT:
To get a parabola going through (1,0) and (a,b), just set:
[tex]y=Ax^{2}+Bx+C[/tex]
and determine A,BC by ther equations:
[tex]0=A+B+C, b=Aa^{2}+Ba+C[/tex]

You'll get many parabolas satisfying your demands.
 
Last edited:
but only i need is a answer of that equation, how do you get that ''x'' out of there?
 
Tom McCurdy said:
I was wondering how you could paramatize a non-linear curve between two points (1,0) and (a,b)

I have been trying to do like a parabolic paramatization but I am getting nowhere

I can get the first point alright

x=x
y=1-x^2
1<x<a
but then you get y=1-x^2

Any suggestions

There is only one straight line between any two points but there are an infinite number of non-linear curves between any two points. If you want a parabolic curve between (1, 0) and (a,b), try this: x= t, y= u+ vx+ wt^2. In order that that pass through (1, 0) we must have x= 1 (so t= a), y= =u+ v+ w= 0. In order that it pass through (a, b) we must have x= a, (so t= a), y= u+ va+ va^2= b. That gives two equations for 3 unknown parameters so there are still an infinite number of such parabolic curves through those 2points. Select 1 by take u, say, equal to 0. Then v+ w= 0 and av+ a^2w= b. Multiply the first equation by a to get av+ aw= 0 and subtract: (a^2- a)w= b so w= b/(a^2- a), v= -1 = -b/(a^2-a). x= t, y= (b/(a^2-a)(t^2- t) works(as long as a is not 1 or 0). If a= 1 or 0, then a parabola with vertical axis will not pass through both points but some other parabola will and, of course, there are still an infinite number of other curves, each with an infinite number of possible parametrizations, that pass through (1, 0) and (a,b).
 

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