/// <summary>
/// Differentiate at point t.
/// </summary>
/// <param name="t">Point t to interpolate at.</param>
/// <returns>Interpolated first derivative at point t.</returns>
/// <seealso cref="IInterpolation.SupportsDifferentiation"/>
/// <seealso cref="DifferentiateAll(double)"/>
public double Differentiate(double t)
{
return(_spline.Differentiate(t));
}
