Daily mathematics serial 54: February 23

2 month 23 Japan XXIII

Mathematical maxims

Although this may seem like a paradox , But all accurate science is governed by approximate ideas .—— Bertram · Russell （Bertrand Russell）

Math exercises

Find the degree of one angle of the five pointed star .

Ancient and Modern Commentaries

Roger · Penrose （Roger Penrose） stay 1970 In, he shocked the whole mathematical world with two simple shapes that were made into a diamond . Use these two shapes of tiles , It can cover a plane with non repeating patterns .1997 year , Manufacturer of Kleenex tissue paper Kimberly - Clarke （Kimberly-Clark）, Use his arrow diamond tiles without Penrose's permission . Penrose tiling helps produce softer with less paper 、 More absorbent cotton paper , And it is more impossible to paste layers without repeated patterns . As a result, Penrose sued Kimberly Clark - Clark's tort .

Kimberly & Co

Began in 1872 In the U.S. , A world-renowned leader in health care , Specializing in personal health care products 、 Large multinational enterprises in the field of household paper and commercial consumption .

Kimberly Clark is a global leader in health care . The company was founded in 1872 year , In the world 35 Countries and regions have production facilities ,41000 employee . Personal health care products 、 Household paper and commercial consumer products are the three core businesses of Kimberly Clark , Annual sales over 180 Billion dollars , Products are sold to