ZermeloAnalyticalCost:

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   Computes the analytical cost for Zermelo's problem.

   Since version 7.
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   Form:
   c = ZermeloAnalyticalCost( theta, x1, y1 )
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   Inputs
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   theta         (2,1) Control angles, [initial final]
   x1            (1,1) x-coordinate
   y1            (1,1) y-coordinate

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   Outputs
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   c             (1,1) Cost

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   Reference: Bryson and Ho, "Applied Optimal Control", Hemisphere Publishing, 1975. 
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