Mathematics Department Faculty of Science Tanta University Tanta Egypt;
Department of Physics and Engineering Mathematics Faculty of Engineering Tanta University Tanta Egypt;
Department of Physics and Engineering Mathematics Faculty of Engineering Tanta University Tanta EgyptKafrelsheikh Higher Institute of Engineering and Technology Kafrelsheikh Egypt;
Homotopy Technique; Nonlinear Vibration; Lagrange’s Equation; Stability;