→ Sfly :O到C 拉出來的圓錐 與平面 Z=1 切出來的曲線就是Γ 09/27 05:46
→ jacky7987 :感謝S大的解釋 可以理解 09/27 21:35
→ jacky7987 :不過要怎麼化成代數式子呢? 因為那個圓錐似乎無法判 09/27 21:35
→ jacky7987 :別長甚麼樣子(畢竟C和P都是會變動的) 09/27 21:36
→ jacky7987 :雖然猜測起來像是橢圓? 09/27 21:37
In |R^3, let C be a circle lying on a plane P which does not pass through
the origin (0,0,0). Let
Γ={(x,y)∈|R^2｜(tx,ty,t)∈C for some t∈|R}
Show that Γ is a quadratic curve. Namely, there is a polynomail F(X,Y) of
total degree 2 such that
Γ={(x,y)∈|R^2｜F(x,y)=0}
Is Γ is ellipse, a parabola or a hyperbola?
感謝大家給與想法
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