Roots function is solving eigth order polynomial equation as fifth order.

I have an equation :

Using coeffs(), i get their coefficients, flip them left to right and then use roots() function to get its zeroes.

But, when , coeffs() function gives coeffs of non-zero terms only,

that is, for fliplr(coeffs(fn)) = [a,c,e,g,i]

So, when I put this coeffs() solution in roots(), it considers it as fifth order polynomial.

How can I get around this problem?

[David Wilson]

Have you looked at coeffsort in the user's group?

https://au.mathworks.com/matlabcentral/fileexchange/6907-coeffsort?s_tid=answers_rc2-3_p6_MLT

[Samridh Sharma]

I hadn't, I'll check.

Answer 1

[Steven Lord]

Specify the 'All' option in your call to coeffs to return all the coefficients, even those that are 0.