# 具体计算一下就更清楚啦(附: 整数相乘及数据拟合)

Thomas Young described the characterization of elasticity that came to be known as Young's modulus, denoted as E, in 1807, and further described it in his Course of Lectures on Natural Philosophy and the Mechanical Arts.

However, the first use of the concept of Young's modulus in experiments was by Giordano Riccati in 1782 – predating Young by 25 years.

Furthermore, the idea can be traced back to a paper by Leonhard Euler published in 1727, some 80 years before Thomas Young.

张老师用时主要在“十位数的2^32 自乘以得到2^64”。我觉得如此相乘需要进行繁琐的加法，耗费时间且容易出错。进行多次乘8 的运算似乎反而容易。大数乘以71，只能进行如下的竖式计算；不过，若乘以72，则可分解为乘以8、再乘以9。

2^10=1,024=10^3+A，而

(2^10)^2=10^6+2A(10^3)+A^2=1,048,576=10^6+B ，那是一眼可以看出；于是

2^60=(10^6+B)^3=10^18+3B(10^12)+3B^2(10^6)+B^3

You M. True-triaxial strength criteria for rock. Inter J Rock Mech Min Sci, 2009, 46(1): 115–127.

You M. Inter J Rock Mech Min Sci, 2012, 54: 114–124, and  2011, 48: 852–863

http://blog.sciencenet.cn/blog-275648-1168349.html

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