| Author |
Comment/Response |
Peter Pein
|
 09/25/09 5:41pm
Hi Nick,
if you want exact expressions without "I", you could try ComplexExpand:
In[1]:= sol = TrigExpand[Solve[x^3 + x^2 - 8*x + 1 == 0,
x] /. (x -> r_) :> x -> ComplexExpand[r,
TargetFunctions -> {Abs, Arg}]]
Out[1]= {{x -> -(1/3) + (5/3)*
Cos[(1/3)*ArcTan[(3*Sqrt[5811])/101]] +
(5*Sin[(1/3)*ArcTan[(3*Sqrt[5811])/101]])/
Sqrt[3]},
{x -> -(1/3) + (5/3)*
Cos[(1/3)*ArcTan[(3*Sqrt[5811])/101]] -
(5*Sin[(1/3)*ArcTan[(3*Sqrt[5811])/101]])/
Sqrt[3]},
{x -> -(1/3) - (10/3)*
Cos[(1/3)*ArcTan[(3*Sqrt[5811])/101]]}}
In[2]:= N[x /. %]
Out[2]= {2.2954157235909167, 0.12728287906017538,
-3.4226986026510926}
Peter
URL: , |
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