“…2, compact support radial basis functions by Chen et al, 3 variational iteration techniques, [4][5][6] the greedy algorithm, 7 local RBF method, 8 semi inverse method, 9,10 iteration perturbation method, 11 variational principle, [12][13][14][15][16] Taylor series method 17 and local methods such as the local Kansa method and local method of approximate particular solutions, 18 He's frequency formulation, 19 and many more. [20][21][22][23][24][25][26][27][28][29] Nonlinear oscillators have been widely utilized to represent numerous physical systems particularly in applied sciences and engineering including the vibrations of plates and beams, the vibrations induced on different structures by fluid flow, the large amplitude oscillations of centrifugal governor systems, the free vibration of a restrained uniform beam undergoing large amplitudes of oscillation and carrying intermediate lumped mass, the oscillations of magneto-elastic mechanical systems or pendulum-like systems, the oscillations of pendulum-like systems or propagation of a short electromagnetic pulse in a nonlinear medium, and so on (see, for example, Refs. [30][31][32][33][34].…”