This paper gives an exact solution for free vibration of a physically nonuniform straight bar with varying section by the use of a class of integrable linear ordinarydifferentialequation.
Ordinary linear differentialequation with its solution is an approximate method to describe dynamic laws of nature, Strickly speaking, most laws of nature is nonlinear.
自然界的运动规律常常用线性微分方程来描述,但进行深入的考虑,更多的运动规律是非线性的。
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The ordinarydifferentialequation of round laminar jet of power-law fluid is derived, and the solution of this equation by numerical integration is obtained.