  In this work, we implement a relatively new analytical technique, the
Improved Amplitude-Frequency Formulation (IAFF) method, approach for solving
accurate approximate analytical solutions for strong nonlinear oscillators,
which may contain high nonlinear terms. This method can be used to obtain
analytic and approximate solutions of different types of fractional
differential equations applied in engineering mathematics. The solutions
obtained are compared with those obtained by the Harmonic balance method (HBM)
and Exact method, showing excellent agreement. We find that these attained
solutions are not only with high degree of accuracy, but also uniformly valid
in the whole solution domain which are so simple-to-do and effective.
