Calculating exact roots of 6th degree polynomial

조회 수: 3 (최근 30일)
Deepayan Bhadra
Deepayan Bhadra 2017년 10월 18일
편집: Walter Roberson 2017년 10월 19일
I've a fat 6x6 matrix E with symbolic variables. I'm trying to compute sqrt(eig(E'E)), ie, the singular values. The answer begins with 'root( ) etc. How do I get MATLAB to solve this 6th degree polynomial and show me more pleasing answers? Thanks a lot.

이 질문에 답변하려면 로그인하십시오.

답변 (1개)

Image Analyst
Image Analyst 2017년 10월 19일
Use roots(), not root().
  댓글 수: 3
이전 댓글 1개 표시
Walter Roberson
Walter Roberson 2017년 10월 19일
root() is the placeholder that replaced RootOf() a couple of releases ago in the Symbolic Toolbox.
Walter Roberson
Walter Roberson 2017년 10월 19일
편집: Walter Roberson 2017년 10월 19일
Which Galois group does it belong to? Because it is not generally possible to solve for exact algebraic roots.
https://en.wikipedia.org/wiki/Sextic_equation
By the way, have you ever looked at how long the roots are just for quartics? About 12500 characters per solution when using bare symbols for the coefficients; much much longer if the coefficients are expressions as you imply is happening for you.
Suppose you managed to find a (say) million character closed form for one of your eigenvalues: realistically, what would you do with it?

댓글을 달려면 로그인하십시오.

카테고리

Help Center 및 File Exchange에서 Polynomials에 대해 자세히 알아보기

태그

Community Treasure Hunt

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

Start Hunting!

Translated by