[討論] solve方程組

[saniao (saniao)]

請問一下
我今天有3個未知數a,b,c待求定
亦有三個方程式eq1,eq2,eq3

我使用symbolic進行解方程組
為什麼每個解都是8x1 syms呢
小弟數學不好請見諒


code如下
syms a b c

eq1=(1+a^2-b^2-c^2)/(1+a^2+b^2+c^2)-0.99768250;
eq2=(1-a^2+b^2-c^2)/(1+a^2+b^2+c^2)-0.75500072;
eq3=(1-a^2-b^2+c^2)/(1+a^2+b^2+c^2)-0.75731587;

[a,b,c]=solve(eq1,eq2,eq3,'a','b','c')


------
結果如下
a =

 -8638450155872395594504574183690^(1/2)/7903815296897390
  8638450155872395594504574183690^(1/2)/7903815296897390
 -8638450155872395594504574183690^(1/2)/7903815296897390
  8638450155872395594504574183690^(1/2)/7903815296897390
 -8638450155872395594504574183690^(1/2)/7903815296897390
  8638450155872395594504574183690^(1/2)/7903815296897390
 -8638450155872395594504574183690^(1/2)/7903815296897390
  8638450155872395594504574183690^(1/2)/7903815296897390

b =

 -10456213264794931385910795^(1/2)/3951907648448695
 -10456213264794931385910795^(1/2)/3951907648448695
  10456213264794931385910795^(1/2)/3951907648448695
  10456213264794931385910795^(1/2)/3951907648448695
 -10456213264794931385910795^(1/2)/3951907648448695
 -10456213264794931385910795^(1/2)/3951907648448695
  10456213264794931385910795^(1/2)/3951907648448695
  10456213264794931385910795^(1/2)/395190764844869

c =

 -82451023629991619035344171910^(1/2)/7903815296897390
 -82451023629991619035344171910^(1/2)/7903815296897390
 -82451023629991619035344171910^(1/2)/7903815296897390
 -82451023629991619035344171910^(1/2)/7903815296897390
  82451023629991619035344171910^(1/2)/7903815296897390
  82451023629991619035344171910^(1/2)/7903815296897390
  82451023629991619035344171910^(1/2)/7903815296897390
  82451023629991619035344171910^(1/2)/7903815296897390

還請板上高手指點迷津
是我用的function有錯嗎
還是正解就是這樣= _=

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→ Joshiki727: 2^3種解  abc的正/負組合……嗎
→ saniao: 那哪一組才是正確的><
→ celestialgod: 你可以double(a)看實數值
→ ejialan: 非線性方程有可能有多解 這題A=a^2,B=b^2,C=c^2可線性化
→ ejialan: 開根號要取正負所以有2^3組解 如果abc沒有限制就都是解
→ ejialan: 有限制 例如a>0,b>0,c>0 解數目就會變少
→ saniao: 好的 我知道了 感謝J大 C大 E大詳細解說