Question

How can the formulation of polynomial be done from its roots?

(a) poly(r), r is a row vector, containing the roots of the polynomial

(b) poly([roots as a coloumn vector])

(c) poly([roots as a row vector])

(d) poly([roots in descending order as a coloumn vector])

This question was posed to me by my college professor while I was bunking the class.

My enquiry is from Algebra topic in section MATLAB Basics of MATLAB

Answer 1

Right option is (b) poly([roots as a coloumn vector])

The best I can explain: To find the roots, one has to store the given roots in a 1*n column vector, say p, and then extract the co-efficients of the polynomial by typing poly(p). This would return the co-efficients of the polynomial in descending order from left to right.