def r_small(self, x, r0):
        """
        Approximate trajectory function for small (:math:`r_0 < \\sigma_r`) oscillations.
        """
        return r0*_np.cos(_np.sqrt(self.k_small) * x)
def r_small(self, x, r0):
        """
        Approximate trajectory function for small (:math:`r_0 < \\sigma_r`) oscillations.
        """
        return r0*_np.cos(_np.sqrt(self.k_small) * x)
def r_small ( self , x , r0 ) : return r0 * _np . cos ( _np . sqrt ( self . k_small ) * x )
Approximate trajectory function for small (:math:`r_0 < \\sigma_r`) oscillations.
Approximate trajectory function for small ( : math : r_0 < \\ sigma_r ) oscillations .