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DirectedInfinity

Usage

DirectedInfinity[ ]表示一个在复平面上方向未知的无穷数量.
DirectedInfinity[z]表示数量为复数z的正实数倍的一个无穷量.


Notes

• 你可以把DirectedInfinity[z] 当作复平面上一个点,这个点可以通过从原点出发,沿点 z的方向走无穷远达到.
• 有下列约定:
"\!\(\*StyleBox[\"\\\"Infinity\\\"\", \"MR\"]\) ""\!\(\*StyleBox[\"\\\"DirectedInfinity[1]\\\"\", \"MR\"]\) "
"\!\(\*StyleBox[\"\\\"-Infinity\\\"\", \"MR\"]\) ""\!\(\*StyleBox[\"\\\"DirectedInfinity[-1]\\\"\", \"MR\"]\) "
"\!\(\*StyleBox[\"\\\"ComplexInfinity\\\"\", \"MR\"]\) ""\!\(\*StyleBox[\"\\\"DirectedInfinity[\\\"\", \"MR\"]\) \!\(\*StyleBox[\"\\\"]\\\"\", \"MR\"]\) "
• 某些算术运算在 DirectedInfinity 量上进行.
• 在OutputForm中,DirectedInfinity[z]根据 Infinity来输出,而DirectedInfinity[ ]作为ComplexInfinity输出.
• 参见Mathematica全书: 3.1.8节.
• 同时参见: Indeterminate.
Further Examples

The FullForm of Infinity shows that it has a direction.

In[1]:=  

Out[1]//FullForm=

Here is an indeterminate form.

In[2]:=  

Out[2]=

This can be thought of as infinity along the complex axis.

In[3]:=  

Out[3]//FullForm=