T****D
发帖数: 2041 | 1 The following are my comments:
(1) The problem is rooted from the following "definition" of the "function":
"定义一个函数：
f(z, x) = 1/(1-z) + (x-z)/(1-z)^2 +(x-z)^2/(1-z)^3+ (x-z)^3/(1-z)^4+ ...
首先需要注意的是这个函数其实是和z无关的，也就是说变化z并不变化f(z,x)。"
which is not proper if one does not know the existence of
(*) 1/(1-z) + (x-z)/(1-z)^2 +(x-z)^2/(1-z)^3+ (x-z)^3/(1-z)^4+ ...
(2) The function f(z,x) can be defined only within the domain where (*) is
convergent.
(3) Now, one needs to make judgment to see where the resulting function f(z
,x) is differentiable ... | b*******8
发帖数: 37364 | 2 有人说了，就这么简单，中学生都会，那需要函数？
1+2+4+。。。=1+2（1+2+4+。。。）
X=1+2X
X=-1 | T****D
发帖数: 2041 | |
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