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Subject: Re: how to plot the ratio of two variables in single axis?
Date: Fri, 25 Jun 2010 21:48:05 +0000 (UTC)
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Dinesh Kumar Kala Sekar <contactdineshraji@gmail.com> wrote in message <1618512900.5126.1277497562574.JavaMail.root@gallium.mathforum.org>...
> Hi all, can anybody help me how to plot a 3d surface graph in which x axis for frequency range, y axis for ratio of two variables say Ri/Re and z axis plotted according to the formula
> 
> omega=2*pi*f;
> r = 1./(1i.*omega.*c);
> z =abs(1/(1/Re + 1/( r + Ri))); 
> 
> here variable c is constant say 10.
> the problem is Re and Ri should not be declared as whole  value to calculate ratio between them. instead as,
> 
> if Ri = Re then value of Ri/Re is 1 this value should be at the mid point of y axis.
> 
> if Ri > Re then value of Ri/Re is greater than 1 this value should be at the right side from the mid point of y axis up-to certain range say, till Ri/Re = 10.
> 
> if Ri < Re then value of Ri/Re is less than 1 this value should be at the left side from the mid point of y axis up-to certain range say, till Ri/Re = 0.1.
> 
> please help me out if anybody knows how to solve this. it would be helpful to carry forward my project work.
- - - - - - - - - - -
  I think you need to explain your problem with greater care and detail.  As it stands, it would appear to be impossible to uniquely determine the z coordinate, knowing only the ratio Ri/Re and frequency f.  That is, for a given value of Ri/Re and f, there is an infinitude of possible values for z depending on the individual values of Ri and Re with that ratio.

  To give you a concrete example of what I am saying, suppose that r = 3 and Ri/Re = 2.  I say z is not uniquely determined.  Let Ri = 2 and Re = 1 and we get z = 5/6.  Yet if Ri = 4 and Re = 2, which has the same ratio, then z = 14/9.  z is therefore not uniquely determined by Ri/Re and r, and there is no way to make the surface plot you are asking for.  z could be any of infinitely many values for the same ratio Ri/Re.

  Note: I realize that your r is pure imaginary, but the above statement of non-uniqueness still holds true nevertheless.

Roger Stafford