function of roots

20 次查看（过去 30 天）
Dwyane Wade
Dwyane Wade 2011-8-15
I have another problem it says:
give the function whose roots are 4, -3, -2, 1/5 and 0.
should I use poly(x) or roots(x)?
  2 个评论
Jan
Jan 2011-8-15
Does this question concern MATLAB? As far as I can see the polynomial with the shown roots can be created manually in some seconds.
Walter Roberson
Walter Roberson 2011-8-15
According to the poly() documentation, it uses eigenvalues. It says,
It is possible to prove that poly(A) produces the coefficients in the characteristic polynomial of a matrix within roundoff error of A. This is true even if the eigenvalues of A are badly conditioned. The traditional algorithms for obtaining the characteristic polynomial, which do not use the eigenvalues, do not have such satisfactory numerical properties.

请先登录，再进行评论。

请先登录，再回答此问题。

采纳的回答

Walter Roberson
Walter Roberson 2011-8-15
roots() is to find the roots of a polynomial that has the given coefficients. The opposite of it is poly.
This is described right in the documentation, http://www.mathworks.com/help/techdoc/ref/poly.html

更多回答（0 个）

类别

在 Help Center 和 File Exchange 中查找有关 Polynomials 的更多信息

标签

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by