
        Find the coefficients a, b, c  of the curve  
 
              y =  ax**2 + bx + c        
  
        that passes through three points.    
          
       x[1],  y[1] 
       x[2],  y[2] 
       x[3],  y[3] 


  Using the given points, we obtain this matrix :

     x**2      x**1      x**0      y

     x[1]**2   x[1]**1   x[1]**0   y[1]
     x[2]**2   x[2]**1   x[2]**0   y[2]
     x[3]**2   x[3]**1   x[3]**0   y[3]


  You can write :

     x**2      x      1   y

     x[1]**2   x[1]   1   y[1]
     x[2]**2   x[2]   1   y[2]
     x[3]**2   x[3]   1   y[3]

   
    x**1 = x,    x**0 = 1.

  Now you can use gaussjordan() on the matrix,
  to find the value of a, b, c.
