 | 超平面H と S^(n-1) にも 通用する 発想 推奨；
陰陽混交がイカン！；
陰 ；
In[21]:=
{x, y} == l*{2, -1}
Out[21]=
{x, y} == {2*l, -l}
In[22]:=
x^2 + y^2 - 1 /. {x -> 2*l, y -> -l}
Out[22]=
-1 + 5*l^2
In[23]:=
Solve[-1 + 5*l^2 == 0, l]
Out[23]=
{{l -> -(1/Sqrt[5])}, {l -> 1/Sqrt[5]}}
In[24]:=
l*{2, -1} /. {l -> 1/Sqrt[5]}
Out[24]=
{2/Sqrt[5], -(1/Sqrt[5])}
In[25]:=
{y - 2*x} /. {x -> 2/Sqrt[5],
y -> -(1/Sqrt[5])}
Out[25]=
{-Sqrt[5]} etc
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In[12]:=
Expand[x^2 + y^2 - 1 /. y -> 2*x + n]
Out[12]=
-1 + n^2 + 4*n*x + 5*x^2
In[13]:=
Solve[% == 0, x]
Out[13]=
{{x -> 1/5*(-2*n - Sqrt[5 - n^2])},
{x -> 1/5*(-2*n + Sqrt[5 - n^2])}}
In[14]:=
Solve[5 - n^2 == 0, n]
Out[14]=
{{n -> -Sqrt[5]}, {n -> Sqrt[5]}}
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