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.
 Further Examples
The FullForm of Infinity shows that it has a direction.
In[1]:=
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Out[1]//FullForm=
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Here is an indeterminate form.
In[2]:=
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Out[2]=
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This can be thought of as infinity along the complex axis.
In[3]:=
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Out[3]//FullForm=
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