FFEccDYDX2:

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   Compute the second derivative of y with respect to x on an ellipse. 
   Here, x is along the major axis and y is along the minor axis.

   This function is called by the "FFEccTrueAnomZInc" function to find the true  
   anomaly at which the maximum cross-track separation occurs, assuming a pure 
   inclination difference (no right ascension difference).  

   Since version 7.
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   Form:
   dydx2 = FFEccDYDX2( nu, e, w );
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   ------
   Inputs
   ------
   nu              (1,N)  True anomaly [rad]
   e                (1)   Eccentricity

   -------
   Outputs
   -------
   dydx2           (1,N)  Second derivative of y w.r.t. x at each true anomaly

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	  Copyright 2004 Princeton Satellite Systems, Inc.
    All rights reserved.
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