摘要
唐代一行(683-727年)在大衍历中首创了通过某地影长的一次观测,求太阳天顶距进而求出该地各节气初日影长的方法,并为此编制了0度到80度的正切函数表。本文就此表的编制方法、观测依据、用途等进行探讨;并通过和古代阿拉伯学者编制的函数表比较,指出此乃世界上最早的正切函数表。
In A. D. 727, Buddhist monk I-Hsing first invented a method for calculating the shadow
length of 8 chi (尺) gnomon dependence of zenith distance of the sun. The relation between
the latter two is a function of tangent. This paper recomposes I-Hsing's table of tangents by
his method and discusses its observational basis, use and so on, pointing out that it is the earli-
est in the world.
出处
《自然科学史研究》
1986年第4期298-309,共12页
Studies in The History of Natural Sciences
