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sz0709

银虫 (小有名气)

[交流] 【求助】解一元三次方程方程

X 3-120x2+194x-100=0
X的立方 减去 120乘以X的平方 加上 194X 减去 100 等于0

[ Last edited by cuplgz on 2008-1-18 at 14:19 ]
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xiaopan099

肯定是对的

放心吧,这个答案是对的
7楼2007-10-16 22:21:26
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xiaopan099

我用matlab算的

>> p=[1 -120 194 -100]

p =

     1  -120   194  -100

>> p1=poly2str(p,'x')

p1 =

   x^3 - 120 x^2 + 194 x - 100

>> r=roots(p1)

r =

   0.6076 + 1.3527i
   0.6076 - 1.3527i
  -1.4657         
   0.9719 + 0.2128i
   0.9719 - 0.2128i
   0.9084 + 0.4005i
   0.9084 - 0.4005i
   0.7237 + 0.5498i
   0.7237 - 0.5498i
   0.6473 + 0.7887i
   0.6473 - 0.7887i
   0.4402 + 0.8662i
   0.4402 - 0.8662i
  -1.0118 + 0.2132i
  -1.0118 - 0.2132i
  -0.9470 + 0.4611i
  -0.9470 - 0.4611i
  -0.6903 + 0.4150i
  -0.6903 - 0.4150i
  -0.7067 + 0.7228i
  -0.7067 - 0.7228i
  -0.5328 + 0.8797i
  -0.5328 - 0.8797i
   0.0915 + 0.9950i
   0.0915 - 0.9950i
  -0.0849 + 0.9673i
  -0.0849 - 0.9673i
  -0.1841 + 0.8466i
  -0.1841 - 0.8466i

>>
2楼2007-10-16 20:50:21
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xiaopan099

算得不对,不好意思
3楼2007-10-16 20:53:34
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sz0709

银虫 (小有名气)

对数学不懂的  给说个明确的答案啊!

X等于多少啊??
4楼2007-10-16 20:54:32
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