Think about the Equation

來源: 於 2010-09-19 12:23:53 [舊帖] [給我悄悄話] 本文已被閱讀：次

There is EQUATION:
X^2/a^2+Y^2/b^2+Z^2/c^2=1,
If a=b=c :all cut face are circles.
a=b not=c,one circle.
a,b,c, total different,no circle.
two circles are impossible.