This paper discussed an elementary solution to the envelope of a kind offamilyofcurves of which the equation was one of the cubic equations in regard to a parameter.
本文论述曲线族的方程为关于参数的三次方程时，其包络曲线方程的初等求法。
2
The normalized form of shear modulus vs. strain amplitude will be shown by a single curve, and that of damping ratio vs. strain amplitude by a familyofcurves or a band zone with shrunk ends.
经归一化后，前者在平面上表示为单一的一根曲线，后者则表现为一簇曲线或两端是尖灭、。
3
In this article, the unified profile expression of the planar CAM mechanism with translation or oscillation follower is established based on the theory of envelopes for 1 parameter familyofcurves.