您好！请教一个问题
我求解4元2次方程组，算出来的结果中还带着部分自变量符号是为啥？
f1=(XD2-XA)**2+(YD2-YA)**2-(XD1-XA)**2-(YD1-YA)**2
F2=(XC2-XB)**2+(YC2-YB)**2-(XC1-XB)**2-(YC1-YB)**2
F3=(XD3-XA)**2+(YD3-YA)**2-(XD1-XA)**2-(YD1-YA)**2
f4=(XC3-XB)**2+(YC3-YB)**2-(XC1-XB)**2-(YC1-YB)**2
def func():
return[f1,F2,F3,f4]
outcome=solve(func(),[XC1,YC1,XD1,YD1])
print(outcome)
部分结果：
(1.04222352941154e-13YC1 - 28812.3123431666sqrt(-1.20460253201585e-9YC1**2 - 0.000176339638892719YC1 + 1) - 28941.1764705819, YC1, -7.36188235294073e-14YD1 - 30538.0946509991sqrt(-1.07229955641681e-9YD1**2 - 0.000125850122056633YD1 + 1) - 31141.1764705864, YD1)
XC2,XD2,YC2,YD2,XC3,YC3,XD3,YD3也都是包含XC1,YC1,XD1,YD1的表达式，XA,XB,YA,YB是已知量赋了值的
