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楼主 |
发表于 2014-3-9 19:55:24
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关于正负等角中心\(E,F\),我们可以得到如下基本公式:
设\(s=\sqrt{a^4-a^2b^2-a^2c^2+b^4-b^2c^2+c^4}\), \(s_0=\sqrt{3(-a^4+2a^2b^2+2a^2c^2-b^4+2b^2c^2-c^4)}\)
\(AE,AF\)满足下列方程:(\(t_1\)实根)
\((9a^4-9a^2b^2-9a^2c^2+9b^4-9b^2c^2+9c^4)t_1^4+(3a^6-12a^4b^2-12a^4c^2+15a^2b^4+9a^2b^2c^2+15a^2c^4-6b^6-3b^4c^2-3b^2c^4-6c^6)t_1^2+(a^2-b^2-bc-c^2)^2(a^2-b^2+bc-c^2)^2=0\)
\(AE=\frac{\sqrt{-a^6+4a^4b^2+4a^4c^2-5a^2b^4-3a^2b^2c^2-5a^2c^4+2b^6+b^4c^2+b^2c^4+2c^6-a^4s_0+a^2b^2s_0+a^2c^2s_0-b^2c^2s_0}}{\sqrt{6}s}\)
\(AF=\frac{\sqrt{-a^6+4a^4b^2+4a^4c^2-5a^2b^4-3a^2b^2c^2-5a^2c^4+2b^6+b^4c^2+b^2c^4+2c^6+a^4s_0-a^2b^2s_0-a^2c^2s_0+b^2c^2s_0}}{\sqrt{6}s}\)
\(BE,BF\)满足下列方程:(\(t_2\)实根)
\((9a^4-9a^2b^2-9a^2c^2+9b^4-9b^2c^2+9c^4)t_2^4+(-6a^6+15a^4b^2-3a^4c^2-12a^2b^4+9a^2b^2c^2-3a^2c^4+3b^6-12b^4c^2+15b^2c^4-6c^6)t_2^2+(a^2-ac-b^2+c^2)^2(a^2+ac-b^2+c^2)^2=0\)
\(BE=\frac{\sqrt{12a^6-30a^4b^2+6a^4c^2+24a^2b^4-18a^2b^2c^2+6a^2c^4-6b^6+24b^4c^2-30b^2c^4+12c^6+6a^2b^2s_0-6a^2c^2s_0-6b^4s_0+6b^2c^2s_0}}{6s}\)
\(BF=\frac{\sqrt{12a^6-30a^4b^2+6a^4c^2+24a^2b^4-18a^2b^2c^2+6a^2c^4-6b^6+24b^4c^2-30b^2c^4+12c^6-6a^2b^2s_0+6a^2c^2s_0+6b^4s_0-6b^2c^2s_0}}{6s}\)
\(CE,CF\)满足下列方程:(\(t_3\)实根)
\((9a^4-9a^2b^2-9a^2c^2+9b^4-9b^2c^2+9c^4)t_3^4+(-6a^6-3a^4b^2+15a^4c^2-3a^2b^4+9a^2b^2c^2-12a^2c^4-6b^6+15b^4c^2-12b^2c^4+3c^6)t_3^2+(a^2+ab+b^2-c^2)^2(a^2-ab+b^2-c^2)^2=0\)
\(CE=\frac{\sqrt{2a^6+a^4b^2-5a^4c^2+a^2b^4-3a^2b^2c^2+4a^2c^4+2b^6-5b^4c^2+4b^2c^4-c^6-a^2b^2s_0+a^2c^2s_0+b^2c^2s_0-c^4s_0}}{\sqrt{6}s}\)
\(CF=\frac{\sqrt{2a^6+a^4b^2-5a^4c^2+a^2b^4-3a^2b^2c^2+4a^2c^4+2b^6-5b^4c^2+4b^2c^4-c^6+a^2b^2s_0-a^2c^2s_0-b^2c^2s_0+c^4s_0}}{\sqrt{6}s}\)
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为了不引起混淆,由于前面已将费马点定义为\(F\),故重新定义正负等角中心为(\E_1,E_2\),注此时定义的\(E_1\)可理解为广义的费马点 \(F\)
即重新定义后的参数如下:
关于正负等角中心\(E_1,E_2\),我们可以得到如下基本公式:
设\(s=\sqrt{a^4-a^2b^2-a^2c^2+b^4-b^2c^2+c^4}\), \(s_0=\sqrt{3(-a^4+2a^2b^2+2a^2c^2-b^4+2b^2c^2-c^4)}\)
\(AE_1,AE_2\)满足下列方程:(\(t_1\)实根)
\((9a^4-9a^2b^2-9a^2c^2+9b^4-9b^2c^2+9c^4)t_1^4+(3a^6-12a^4b^2-12a^4c^2+15a^2b^4+9a^2b^2c^2+15a^2c^4-6b^6-3b^4c^2-3b^2c^4-6c^6)t_1^2+(a^2-b^2-bc-c^2)^2(a^2-b^2+bc-c^2)^2=0\)
\(AE_1=\frac{\sqrt{-a^6+4a^4b^2+4a^4c^2-5a^2b^4-3a^2b^2c^2-5a^2c^4+2b^6+b^4c^2+b^2c^4+2c^6-a^4s_0+a^2b^2s_0+a^2c^2s_0-b^2c^2s_0}}{\sqrt{6}s}\)
\(AE_2=\frac{\sqrt{-a^6+4a^4b^2+4a^4c^2-5a^2b^4-3a^2b^2c^2-5a^2c^4+2b^6+b^4c^2+b^2c^4+2c^6+a^4s_0-a^2b^2s_0-a^2c^2s_0+b^2c^2s_0}}{\sqrt{6}s}\)
\(BE_1,BE_2\)满足下列方程:(\(t_2\)实根)
\((9a^4-9a^2b^2-9a^2c^2+9b^4-9b^2c^2+9c^4)t_2^4+(-6a^6+15a^4b^2-3a^4c^2-12a^2b^4+9a^2b^2c^2-3a^2c^4+3b^6-12b^4c^2+15b^2c^4-6c^6)t_2^2+(a^2-ac-b^2+c^2)^2(a^2+ac-b^2+c^2)^2=0\)
\(BE_1=\frac{\sqrt{12a^6-30a^4b^2+6a^4c^2+24a^2b^4-18a^2b^2c^2+6a^2c^4-6b^6+24b^4c^2-30b^2c^4+12c^6+6a^2b^2s_0-6a^2c^2s_0-6b^4s_0+6b^2c^2s_0}}{6s}\)
\(BE_2=\frac{\sqrt{12a^6-30a^4b^2+6a^4c^2+24a^2b^4-18a^2b^2c^2+6a^2c^4-6b^6+24b^4c^2-30b^2c^4+12c^6-6a^2b^2s_0+6a^2c^2s_0+6b^4s_0-6b^2c^2s_0}}{6s}\)
\(CE_1,CE_2\)满足下列方程:(\(t_3\)实根)
\((9a^4-9a^2b^2-9a^2c^2+9b^4-9b^2c^2+9c^4)t_3^4+(-6a^6-3a^4b^2+15a^4c^2-3a^2b^4+9a^2b^2c^2-12a^2c^4-6b^6+15b^4c^2-12b^2c^4+3c^6)t_3^2+(a^2+ab+b^2-c^2)^2(a^2-ab+b^2-c^2)^2=0\)
\(CE_1=\frac{\sqrt{2a^6+a^4b^2-5a^4c^2+a^2b^4-3a^2b^2c^2+4a^2c^4+2b^6-5b^4c^2+4b^2c^4-c^6-a^2b^2s_0+a^2c^2s_0+b^2c^2s_0-c^4s_0}}{\sqrt{6}s}\)
\(CE_2=\frac{\sqrt{2a^6+a^4b^2-5a^4c^2+a^2b^4-3a^2b^2c^2+4a^2c^4+2b^6-5b^4c^2+4b^2c^4-c^6+a^2b^2s_0-a^2c^2s_0-b^2c^2s_0+c^4s_0}}{\sqrt{6}s}\)
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