24小时热门版块排行榜    

查看: 1136  |  回复: 9
当前主题已经存档。
当前只显示满足指定条件的回帖,点击这里查看本话题的所有回帖

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 ]
回复此楼
已阅   回复此楼   关注TA 给TA发消息 送TA红花 TA的回帖

xiaopan099

>> p2=poly2str(p,'x')

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

p =

     1  -120   194  -100
p2 =

   x^3 - 120 x^2 + 194 x - 100

>> solve(p2)
??? Error using ==> solve
'   x^3 - 120 x^2 + 194 x - 100' is not a valid expression or equation.

这个方程好象解不出的.
高手指教一下
5楼2007-10-16 21:17:17
已阅   回复此楼   关注TA 给TA发消息 送TA红花 TA的回帖
查看全部 10 个回答

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
已阅   回复此楼   关注TA 给TA发消息 送TA红花 TA的回帖

xiaopan099

算得不对,不好意思
3楼2007-10-16 20:53:34
已阅   回复此楼   关注TA 给TA发消息 送TA红花 TA的回帖

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
已阅   回复此楼   关注TA 给TA发消息 送TA红花 TA的回帖
普通表情 龙 兔 虎 猫 高级回复 (可上传附件)
最具人气热帖推荐 [查看全部] 作者 回/看 最后发表
[公派出国] 售SCI一区文章,我:8.O.551.O.5.4,科目全,可伽急 +3 czAiolzR0IJC 2026-11-10 7/350 2026-11-12 06:47 by 9fOTqj074tIg
[考研] 售SCI一区T0P文章,我:8O.55.1.O.54,科目全,可伽急 +3 G2rhSvqvhNzl 2026-11-10 6/300 2026-11-12 06:25 by 9fOTqj074tIg
[基金申请] 售SCI一区文章,我:8.O.551.O.5.4,科目全,可伽急 +4 G2rhSvqvhNzl 2026-11-10 6/300 2026-11-12 06:23 by 9fOTqj074tIg
[公派出国] 售SCI一区文章,我:8.O.551.O.5.4,科目全,可伽急 +3 G2rhSvqvhNzl 2026-11-10 4/200 2026-11-12 06:14 by 9fOTqj074tIg
[硕博家园] 售SCI一区T0P文章,我:8.O.55.1.O.5.4,科目全,可+急 +3 C6CRn66RYYXS 2026-11-10 5/250 2026-11-12 06:03 by 9fOTqj074tIg
[基金申请] 售SCI一区T0P文章,我:8O.55.1.O.54,科目全,可伽急 +4 C6CRn66RYYXS 2026-11-10 5/250 2026-11-12 05:55 by 9fOTqj074tIg
[基金申请] 售SCI一区T0P文章,我:8.O.55.1.O.54,科目齐全,可+急 +5 FChKX8meu1ds 2026-11-09 7/350 2026-11-12 05:30 by 9fOTqj074tIg
[硕博家园] 售SCI一区T0P文章,我:8.O.55.1.O.5.4,科目全,可+急 +4 FChKX8meu1ds 2026-11-09 8/400 2026-11-12 05:28 by 9fOTqj074tIg
[考研] 售SCI一区文章,我:8.O.55.1.O.54,科目齐全,可伽急 +6 FChKX8meu1ds 2026-11-09 9/450 2026-11-12 05:19 by 9fOTqj074tIg
[考研] 售SCI一区文章,我:8O5.5.1.O5.4,科目全,可伽急 +7 cqv1zKnzd7hr 2026-11-09 11/550 2026-11-12 05:08 by 9fOTqj074tIg
[考研] 售SCI一区T0P文章,我:8O.55.1.O.5.4,科目齐全,可+急 +5 cqv1zKnzd7hr 2026-11-09 8/400 2026-11-12 05:08 by 9fOTqj074tIg
[硕博家园] 售SCI-T0P文章,我:8O.5.5.1.O.54,科目齐全,可+急 +7 cqv1zKnzd7hr 2026-11-09 11/550 2026-11-12 05:05 by 9fOTqj074tIg
[教师之家] 售SCI一区T0P文章,我:8.O55.1.O.54,科目全,可十急 +7 zSbvVX9JFl9J 2026-11-09 11/550 2026-11-12 04:54 by 9fOTqj074tIg
[考研] 售一区SCI文章T0P,我:8O.551.O54,科目全,可十急 +6 zSbvVX9JFl9J 2026-11-09 7/350 2026-11-12 04:49 by 9fOTqj074tIg
[基金申请] 售SCI-T0P文章,我:8O.5.5.1.O.54,科目齐全,可+急 +3 Z7qfCsdIiD1T 2026-11-10 5/250 2026-11-12 02:36 by 9fOTqj074tIg
[考研] 售一区SCI文章T0P,我:8O.551.O54,科目全,可十急 +3 Z7qfCsdIiD1T 2026-11-10 4/200 2026-11-12 02:23 by 9fOTqj074tIg
[考研] 售SCI一区文章,我:8O5.5.1.O5.4,科目全,可伽急 +3 G2rhSvqvhNzl 2026-11-10 5/250 2026-11-12 01:50 by 9fOTqj074tIg
[硕博家园] 售SCI-T0P文章,我:8O.5.5.1.O.54,科目齐全,可+急 +4 G2rhSvqvhNzl 2026-11-10 5/250 2026-11-11 17:58 by TgvkbZZl9tqB
[考博] 申请环境,微生物方向博士 +3 浅笑09 2026-11-08 3/150 2026-11-10 12:44 by 可淡不可忘
[教师之家] 售SCI一区T0P文章,我:8.O.55.1.O.54,科目齐全,可+急 +4 5sJFDKp2kwuI 2026-11-06 8/400 2026-11-08 23:01 by l48hFd8Nwae2
信息提示
请填处理意见