主题: [MATLAB基础] 符号解三次方程有误?
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旧 2012-11-07, 19:12   #3
zsy312
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默认 回复: 符号解三次方程有误?

代码:
syms x
s=solve(x^3+3*x-1,x);
s=real(s)+1i*imag(s)
ds=double(s)
输出:
代码:
s =
 
                                                                1/2*(4+4*5^(1/2))^(1/3)-2/(4+4*5^(1/2))^(1/3)
 -1/4*(4+4*5^(1/2))^(1/3)+1/(4+4*5^(1/2))^(1/3)+1/2*i*3^(1/2)*(1/2*(4+4*5^(1/2))^(1/3)+2/(4+4*5^(1/2))^(1/3))
 -1/4*(4+4*5^(1/2))^(1/3)+1/(4+4*5^(1/2))^(1/3)-1/2*i*3^(1/2)*(1/2*(4+4*5^(1/2))^(1/3)+2/(4+4*5^(1/2))^(1/3))
 
 

ds =

   0.3222          
  -0.1611 + 1.7544i
  -0.1611 - 1.7544i
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