# Documentation

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# sym2poly

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

## Description

example

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 ${c}_{1}{x}^{n-1}+{c}_{2}{x}^{n-2}+...+{c}_{n}$, 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

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Polynomial, specified as a symbolic expression.

## Output Arguments

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Polynomial coefficients, returned as a numeric row vector.

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### 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].