Comments and Research on Proofs of Chain Rule

In this paper we point out that the proofs of Chain Rule in many intensively used textbooks are not strict an construct anexa mple of a composite function f(u) which is differentiable with respects t o the independednt variable u, but is not differentiable with respect to the dependent variable u=g(x). A strict proof of Chain Rule is presented. Incon sistency of the form and content of Chain Rule is disclosed.

延边黄牛幼牛正常生长发育曲线研究

本研究是应用复含函数回归式y^^=a＋b（X-Xn）／[k＋kh（X—X0）]对延边黄牛24个月龄体重、体尺的平均值和上下限66项实测资料计算回归式和各月龄估测值，结果公、母牛体重实测植与估测值之间的∑（y-y^^）^2分别为286．55、176．24，拐点偏差为0．7、0．3个月龄，比应用y^^=k／（1＋ae^hx）计算的∑（y-y^^）^2低5214．23、4007．05，计算公、母牛体尺资料平均值的估测值与实测值的∑（y-y^^）^2,除母牛胸宽平均值外都比应用y^^=a＋bx＋cx^2计算结果低，与实测值的吻合度较高并能克服二次回归式和布劳迪回归式所存在的缺点。