Matlab Q, if I use the following code I get a diffrent answe than if I extractd

Question

Matlab Q,

if I use the following code I get a diffrent answe than if I extractd the Coeffs manually and asked for roots any ideas?

cd=fliplr(coeffs(2*s^4+s^3+5*s^2+36)) % extract Coefficents and flip array name it cn

roots(cd)

ans =

(44869^(1/2)/24 - 475/54)^(1/3) - 29/(36*(44869^(1/2)/24 - 475/54)^(1/3)) - 1/6
29/(72*(44869^(1/2)/24 - 475/54)^(1/3)) - (3^(1/2)*(29/(36*(44869^(1/2)/24 - 475/54)^(1/3)) + (44869^(1/2)/24 - 475/54)^(1/3))*i)/2 - (44869^(1/2)/24 - 475/54)^(1/3)/2 - 1/6
(3^(1/2)*(29/(36*(44869^(1/2)/24 - 475/54)^(1/3)) + (44869^(1/2)/24 - 475/54)^(1/3))*i)/2 + 29/(72*(44869^(1/2)/24 - 475/54)^(1/3)) - (44869^(1/2)/24 - 475/54)^(1/3)/2 - 1/6

>>

Explanation / Answer

use

vpa(roots(cd))

or

simplify(roots(cd))

or

double(roots(cd))

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