KdV equation Approximate analytic solution 1 Boundary feedback 1 Decay (organic) 1 H-curve 1 Internal feedback 1 Kdv equation 1 Korteweg-de Vries equation 1 Korteweg-de Vries-equation 1 Lyapunov functionals 1 New homotopy analysis method 1 Spatial domains 1 Stability 1 Stability results 1 System of first order differential equation 1 Time delay 1 Time dependent 1 Time-depending delay 1 Time-varying delay 1