sym2poly

Extract vector of all numeric coefficients, including zeros, from symbolic polynomial

Syntax

c = sym2poly(p)

Description

c = sym2poly(p) returns the numeric vector of coefficients c of the symbolic polynomial p. The returned vector c includes all coefficients, including those equal 0.

sym2poly returns coefficients in order of descending powers of the polynomial variable. If $$c_1{x}^{n-1}+c_2{x}^{n-2}+\mathrm{...}+c_n$$, then c = sym2poly(p) returns c = [c1 c2 ... cn].

Examples

Extract Numeric Coefficients of Polynomial

Create row vectors of coefficients of symbolic polynomials.

Extract integer coefficients of a symbolic polynomial into a numeric row vector.

syms x
c = sym2poly(x^3 - 2*x - 5)

c =
     1     0    -2    -5

Extract rational and integer coefficients of a symbolic polynomial into a vector. Because sym2poly returns numeric double-precision results, it approximates exact rational coefficients with double-precision numbers.

c = sym2poly(1/2*x^3 - 2/3*x - 5)

c =
    0.5000         0   -0.6667   -5.0000

Input Arguments

p — Polynomial

symbolic expression

Polynomial, specified as a symbolic expression.

Output Arguments

c — Polynomial coefficients

numeric row vector

Polynomial coefficients, returned as a numeric row vector.

Tips

• To extract symbolic coefficients of a polynomial, use coeffs. This function returns a symbolic vector of coefficients and omits all zeros. For example, syms a b x; c = coeffs(a*x^3 - 5*b,x) returns c = [ -5*b, a].

Version History

Introduced before R2006a