The Pythagorean theorem(translation is 毕达哥拉斯定理
) in ancient Chinese mathematics is called 勾股定理
.
Typically, the mathematical expression we use to describe the Pythagorean Theorem is
a^2
+ b^2
= c^2
.
At the same time, we usually think of the hypotenuse of a right triangle as c, the short right side as a, and the long right side as b.
Therefore, a is shorter than b, and b is shorter than c.(a <= b
, b < c
)
Description of Pythagorean theorem in ancient Chinese mathematics
短面曰勾,长面曰股,相与结角曰弦。勾短其股,股短其弦。——《九章算术·勾股》
译文:
在直角三角形中,短的边称为勾,长的边称为股,与它们分别形成直角的边为弦。勾的长度比股短,股的长度比弦短。
In a right triangle, the short side is called 勾
, the long side is called 股
, and the side forming a right angle with them is 弦
.
勾
is shorter than 股
, and 股
is shorter than 弦
.(勾 <= 股
,股 < 弦
)
Note that 冪
is the traditional Chinese character for 幂
, and the 幂
mentioned below all refer to 冪
.
"the product of two numbers" means 两数之积
in Chinese.
"multiplying
"multiplying a number by itself" means 自乘(一个数与自身相乘)
in Chinese.
Now go back to the Pythagorean theorem(毕达哥拉斯定理,勾股定理).
Typically, the mathematical expression we use to describe the Pythagorean Theorem is a^2
+ b^2
= c^2
.
At the same time, we usually think of the hypotenuse of a right triangle as c, the short right side as a, and the long right side as b.
Therefore, a is shorter than b, and b is shorter than c.(a <= b
, b < c
)
Description of Pythagorean theorem in ancient Chinese mathematics
短面曰勾,长面曰股,相与结角曰弦。勾短其股,股短其弦。——《九章算术·勾股》
译文:
在直角三角形中,短的边称为勾,长的边称为股,与它们分别形成直角的边为弦。勾的长度比股短,股的长度比弦短。
In a right triangle, the short side is called 勾
, the long side is called 股
, and the side forming a right angle with them is 弦
.
勾
is shorter than 股
, and 股
is shorter than 弦
.(勾 <= 股
,股 < 弦
)
Now back to the question.
about 朱幂
and 黄幂
:
朱
means 赤色
, indicate red.
朱,赤心木,松柏属。——《说文解字》
方幂
here means square, can be replaced by the word 幂自乘
, its explanation is above.